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Mota SI, Fão L, Coelho P, Rego AC. Uncovering the Early Events Associated with Oligomeric Aβ-Induced Src Activation. Antioxidants (Basel) 2023; 12:1770. [PMID: 37760073 PMCID: PMC10525724 DOI: 10.3390/antiox12091770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 09/09/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
Soluble Aβ1-42 oligomers (AβO) are formed in the early stages of Alzheimer's disease (AD) and were previously shown to trigger enhanced Ca2+ levels and mitochondrial dysfunction via the activation of N-methyl-D-aspartate receptors (NMDAR). Src kinase is a ubiquitous redox-sensitive non-receptor tyrosine kinase involved in the regulation of several cellular processes, which was demonstrated to have a reciprocal interaction towards NMDAR activation. However, little is known about the early-stage mechanisms associated with AβO-induced neurodysfunction involving Src. Thus, in this work, we analysed the influence of brief exposure to oligomeric Aβ1-42 on Src activation and related mechanisms involving mitochondria and redox changes in mature primary rat hippocampal neurons. Data show that brief exposure to AβO induce H2O2-dependent Src activation involving different cellular events, including NMDAR activation and mediated intracellular Ca2+ rise, enhanced cytosolic and subsequent mitochondrial H2O2 levels, accompanied by mild mitochondrial fragmentation. Interestingly, these effects were prevented by Src inhibition, suggesting a feedforward modulation. The current study supports a relevant role for Src kinase activation in promoting the loss of postsynaptic glutamatergic synapse homeostasis involving cytosolic and mitochondrial ROS generation after brief exposure to AβO. Therefore, restoring Src activity can constitute a protective strategy for mitochondria and related hippocampal glutamatergic synapses.
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Affiliation(s)
- Sandra I. Mota
- CNC-UC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; (S.I.M.); (L.F.); (P.C.)
- CIBB-Center for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-504 Coimbra, Portugal
- IIIUC-Institute of Interdisciplinary Research, University of Coimbra, 3030-789 Coimbra, Portugal
| | - Lígia Fão
- CNC-UC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; (S.I.M.); (L.F.); (P.C.)
- CIBB-Center for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Patrícia Coelho
- CNC-UC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; (S.I.M.); (L.F.); (P.C.)
- CIBB-Center for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - A. Cristina Rego
- CNC-UC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; (S.I.M.); (L.F.); (P.C.)
- CIBB-Center for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-504 Coimbra, Portugal
- Institute of Biochemistry, Faculty of Medicine, University of Coimbra, 3000-354 Coimbra, Portugal
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Suelves N, Saleki S, Ibrahim T, Palomares D, Moonen S, Koper MJ, Vrancx C, Vadukul DM, Papadopoulos N, Viceconte N, Claude E, Vandenberghe R, von Arnim CAF, Constantinescu SN, Thal DR, Decottignies A, Kienlen-Campard P. Senescence-related impairment of autophagy induces toxic intraneuronal amyloid-β accumulation in a mouse model of amyloid pathology. Acta Neuropathol Commun 2023; 11:82. [PMID: 37198698 DOI: 10.1186/s40478-023-01578-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 05/07/2023] [Indexed: 05/19/2023] Open
Abstract
Aging is the main risk factor for Alzheimer's disease (AD) and other neurodegenerative pathologies, but the molecular and cellular changes underlying pathological aging of the nervous system are poorly understood. AD pathology seems to correlate with the appearance of cells that become senescent due to the progressive accumulation of cellular insults causing DNA damage. Senescence has also been shown to reduce the autophagic flux, a mechanism involved in clearing damaged proteins from the cell, and such impairment has been linked to AD pathogenesis. In this study, we investigated the role of cellular senescence on AD pathology by crossing a mouse model of AD-like amyloid-β (Aβ) pathology (5xFAD) with a mouse model of senescence that is genetically deficient for the RNA component of the telomerase (Terc-/-). We studied changes in amyloid pathology, neurodegeneration, and the autophagy process in brain tissue samples and primary cultures derived from these mice by complementary biochemical and immunostaining approaches. Postmortem human brain samples were also processed to evaluate autophagy defects in AD patients. Our results show that accelerated senescence produces an early accumulation of intraneuronal Aβ in the subiculum and cortical layer V of 5xFAD mice. This correlates with a reduction in amyloid plaques and Aβ levels in connecting brain regions at a later disease stage. Neuronal loss was specifically observed in brain regions presenting intraneuronal Aβ and was linked to telomere attrition. Our results indicate that senescence affects intraneuronal Aβ accumulation by impairing autophagy function and that early autophagy defects can be found in the brains of AD patients. Together, these findings demonstrate the instrumental role of senescence in intraneuronal Aβ accumulation, which represents a key event in AD pathophysiology, and emphasize the correlation between the initial stages of amyloid pathology and defects in the autophagy flux.
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Affiliation(s)
- Nuria Suelves
- Aging and Dementia Group, Cellular and Molecular Division (CEMO), Institute of Neuroscience (IoNS), UCLouvain, Brussels, Belgium
| | - Shirine Saleki
- Aging and Dementia Group, Cellular and Molecular Division (CEMO), Institute of Neuroscience (IoNS), UCLouvain, Brussels, Belgium
| | - Tasha Ibrahim
- Aging and Dementia Group, Cellular and Molecular Division (CEMO), Institute of Neuroscience (IoNS), UCLouvain, Brussels, Belgium
| | - Debora Palomares
- Aging and Dementia Group, Cellular and Molecular Division (CEMO), Institute of Neuroscience (IoNS), UCLouvain, Brussels, Belgium
| | - Sebastiaan Moonen
- Laboratory for Neuropathology, Department of Imaging and Pathology, Leuven Brain Institute (LBI), KU Leuven, Leuven, Belgium
- Laboratory for the Research of Neurodegenerative Diseases, Department of Neurosciences, Leuven Brain Institute (LBI), KU Leuven, Leuven, Belgium
- Vlaams Instituut Voor Biotechnologie (VIB) Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Marta J Koper
- Laboratory for Neuropathology, Department of Imaging and Pathology, Leuven Brain Institute (LBI), KU Leuven, Leuven, Belgium
- Laboratory for the Research of Neurodegenerative Diseases, Department of Neurosciences, Leuven Brain Institute (LBI), KU Leuven, Leuven, Belgium
- Vlaams Instituut Voor Biotechnologie (VIB) Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Céline Vrancx
- Aging and Dementia Group, Cellular and Molecular Division (CEMO), Institute of Neuroscience (IoNS), UCLouvain, Brussels, Belgium
- Laboratory for Membrane Trafficking, Department of Neurosciences, Vlaams Instituut Voor Biotechnologie (VIB) Center for Brain and Disease Research, KU Leuven, Leuven, Belgium
| | - Devkee M Vadukul
- Aging and Dementia Group, Cellular and Molecular Division (CEMO), Institute of Neuroscience (IoNS), UCLouvain, Brussels, Belgium
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, UK
| | - Nicolas Papadopoulos
- Ludwig Institute for Cancer Research, Brussels, Belgium
- SIGN Unit, de Duve Institute, UCLouvain, Brussels, Belgium
| | - Nikenza Viceconte
- Genetic and Epigenetic Alterations of Genomes Unit, de Duve Institute, UCLouvain, Brussels, Belgium
- CENTOGENE GmbH, 18055, Rostock, Germany
| | - Eloïse Claude
- Genetic and Epigenetic Alterations of Genomes Unit, de Duve Institute, UCLouvain, Brussels, Belgium
| | - Rik Vandenberghe
- Laboratory for Cognitive Neurology, Department of Neurosciences, Leuven Brain Institute (LBI), KU Leuven (University of Leuven), Leuven, Belgium
- Department of Neurology, University Hospital Leuven, Leuven, Belgium
| | - Christine A F von Arnim
- Department of Neurology, University of Ulm, Ulm, Germany
- Department of Geriatrics, University Medical Center Göttingen, Göttingen, Germany
| | - Stefan N Constantinescu
- Ludwig Institute for Cancer Research, Brussels, Belgium
- SIGN Unit, de Duve Institute, UCLouvain, Brussels, Belgium
- Walloon Excellence in Life Sciences and Biotechnology (WELBIO), Brussels, Belgium
- Nuffield Department of Medicine, Ludwig Institute for Cancer Research, Oxford University, Oxford, UK
| | - Dietmar Rudolf Thal
- Laboratory for Neuropathology, Department of Imaging and Pathology, Leuven Brain Institute (LBI), KU Leuven, Leuven, Belgium
- Department of Pathology, University Hospital Leuven, Leuven, Belgium
| | - Anabelle Decottignies
- Genetic and Epigenetic Alterations of Genomes Unit, de Duve Institute, UCLouvain, Brussels, Belgium
| | - Pascal Kienlen-Campard
- Aging and Dementia Group, Cellular and Molecular Division (CEMO), Institute of Neuroscience (IoNS), UCLouvain, Brussels, Belgium.
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Yu Y, Gao Y, Winblad B, Tjernberg LO, Schedin-Weiss S. A Super-Resolved View of the Alzheimer's Disease-Related Amyloidogenic Pathway in Hippocampal Neurons. J Alzheimers Dis 2021; 83:833-852. [PMID: 34366358 PMCID: PMC8543249 DOI: 10.3233/jad-215008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Processing of the amyloid-β protein precursor (AβPP) is neurophysiologically important due to the resulting fragments that regulate synapse biology, as well as potentially harmful due to generation of the 42 amino acid long amyloid β-peptide (Aβ42), which is a key player in Alzheimer's disease. OBJECTIVE Our aim was to clarify the subcellular locations of the fragments involved in the amyloidogenic pathway in primary neurons with a focus on Aβ42 and its immediate substrate AβPP C-terminal fragment (APP-CTF). To overcome the difficulties of resolving these compartments due to their small size, we used super-resolution microscopy. METHODS Mouse primary hippocampal neurons were immunolabelled and imaged by stimulated emission depletion (STED) microscopy, including three-dimensional three-channel imaging, and quantitative image analyses. RESULTS The first (β-secretase) and second (γ-secretase) cleavages of AβPP were localized to functionally and distally distinct compartments. The β-secretase cleavage was observed in early endosomes in soma, where we were able to show that the liberated N- and C-terminal fragments were sorted into distinct vesicles budding from the early endosomes. Lack of colocalization of Aβ42 and APP-CTF in soma suggested that γ-secretase cleavage occurs in neurites. Indeed, APP-CTF was, in line with Aβ42 in our previous study, enriched in the presynapse but absent from the postsynapse. In contrast, full-length AβPP was not detected in either the pre- or the postsynaptic side of the synapse. Furthermore, we observed that endogenously produced and endocytosed Aβ42 were localized in different compartments. CONCLUSION These findings provide critical super-resolved insight into amyloidogenic AβPP processing in primary neurons.
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Affiliation(s)
- Yang Yu
- Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna, Sweden
| | - Yang Gao
- Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna, Sweden
| | - Bengt Winblad
- Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna, Sweden.,Theme Inflammation and Aging, Karolinska University Hospital, Huddinge, Sweden
| | - Lars O Tjernberg
- Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna, Sweden
| | - Sophia Schedin-Weiss
- Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna, Sweden
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4
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Mota SI, Pita I, Águas R, Tagorti S, Virmani A, Pereira FC, Rego AC. Mechanistic perspectives on differential mitochondrial-based neuroprotective effects of several carnitine forms in Alzheimer's disease in vitro model. Arch Toxicol 2021; 95:2769-2784. [PMID: 34164711 DOI: 10.1007/s00204-021-03104-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 06/15/2021] [Indexed: 11/29/2022]
Abstract
Mitochondrial deregulation has emerged as one of the earliest pathological events in Alzheimer's disease (AD), the most common age-related neurodegenerative disorder. Improvement of mitochondrial function in AD has been considered a relevant therapeutic approach. L-carnitine (LC), an amino acid derivative involved in the transport of long-chain fatty acids into mitochondria, was previously demonstrated to improve mitochondrial function, having beneficial effects in neurological disorders; moreover, acetyl-L-carnitine (ALC) is currently under phase 4 clinical trial for AD (ClinicalTrials.gov NCT01320527). Thus, in the present study, we investigated the impact of different forms of carnitines, namely LC, ALC and propionyl-L-carnitine (PLC) on mitochondrial toxicity induced by amyloid-beta peptide 1-42 oligomers (AβO; 1 μM) in mature rat hippocampal neurons. Our results indicate that 5 mM LC, ALC and PLC totally rescued the mitochondrial membrane potential and alleviated both the decrease in oxygen consumption rates and the increase in mitochondrial fragmentation induced by AβO. These could contribute to the prevention of neuronal death by apoptosis. Moreover, only ALC ameliorated AβO-evoked changes in mitochondrial movement by reducing the number of stationary mitochondria and promoting reversal mitochondrial movement. Data suggest that carnitines (LC, ALC and PLC) may act differentially to counteract changes in mitochondrial function and movement in neurons subjected to AβO, thus counteracting AD-related pathological phenotypes.
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Affiliation(s)
- Sandra I Mota
- CNC-Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-504, Coimbra, Portugal
- IIIUC - Institute for Interdisciplinary Research, University of Coimbra, 3030-789, Coimbra, Portugal
| | - Inês Pita
- Institute of Pharmacology and Experimental Therapeutics, Faculty of Medicine, University of Coimbra, 3004-504, Coimbra, Portugal
| | - Rodolfo Águas
- CNC-Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-504, Coimbra, Portugal
| | - Slah Tagorti
- Alfasigma B.V, 3528 BG, Utrecht, The Netherlands
| | | | - Frederico C Pereira
- Institute of Pharmacology and Experimental Therapeutics, Faculty of Medicine, University of Coimbra, 3004-504, Coimbra, Portugal.
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3004-504, Coimbra, Portugal.
| | - A Cristina Rego
- CNC-Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-504, Coimbra, Portugal.
- Institute of Biochemistry, Faculty of Medicine, University of Coimbra, 3004-504, Coimbra, Portugal.
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5
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Rahman MS, Uddin MS, Rahman MA, Samsuzzaman M, Behl T, Hafeez A, Perveen A, Barreto GE, Ashraf GM. Exploring the Role of Monoamine Oxidase Activity in Aging and Alzheimer's Disease. Curr Pharm Des 2021; 27:4017-4029. [PMID: 34126892 DOI: 10.2174/1381612827666210612051713] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 04/06/2021] [Indexed: 11/22/2022]
Abstract
Monoamine oxidases (MAOs) are a family of flavin adenine dinucleotide-dependent enzymes that exert a crucial role in the metabolism of neurotransmitters of the central nervous system. The impaired function of MAOs is associated with copious brain diseases. The alteration of monoamine metabolism is a characteristics feature of aging. MAO plays a crucial role in the pathogenesis of Alzheimer's disease (AD) - a progressive neurodegenerative disorder associated with an excessive accumulation of amyloid-beta (Aβ) peptide and neurofibrillary tangles (NFTs). Activated MAO has played a critical role in the development of amyloid plaques from Aβ, as well as the formation of the NFTs. In the brain, MAO mediated metabolism of monoamines is the foremost source of reactive oxygen species formation. The elevated level of MAO-B expression in astroglia has been reported in the AD brains adjacent to amyloid plaques. Increased MAO-B activity in the cortical and hippocampal regions is associated with AD. This review describes the pathogenic mechanism of MAOs in aging as well as the development and propagation of Alzheimer's pathology.
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Affiliation(s)
- Md Sohanur Rahman
- Department of Biochemistry and Molecular Biology, Trust University, Ruiya, Nobogram Road, Barishal 8200, Bangladesh
| | - Md Sahab Uddin
- Department of Pharmacy, Southeast University, Dhaka, Bangladesh
| | - Md Ataur Rahman
- Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology, Seoul. Korea
| | - Md Samsuzzaman
- Department of Food and Life Science, Pukyong National University, Busan 48513. Korea
| | - Tapan Behl
- Glocal School of Pharmacy, Glocal University, Saharanpur, India
| | - Abdul Hafeez
- Glocal School of Pharmacy, Glocal University, Saharanpur, India
| | - Asma Perveen
- Glocal School of Life Sciences, Glocal University, Saharanpur, India
| | - George E Barreto
- Department of Biological Sciences, University of Limerick, Limerick. Ireland
| | - Ghulam Md Ashraf
- Pre-Clinical Research Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah. Saudi Arabia
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6
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Amyloid-Beta Mediates Homeostatic Synaptic Plasticity. J Neurosci 2021; 41:5157-5172. [PMID: 33926999 PMCID: PMC8211553 DOI: 10.1523/jneurosci.1820-20.2021] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 03/02/2021] [Accepted: 03/28/2021] [Indexed: 12/25/2022] Open
Abstract
The physiological role of the amyloid-precursor protein (APP) is insufficiently understood. Recent work has implicated APP in the regulation of synaptic plasticity. Substantial evidence exists for a role of APP and its secreted ectodomain APPsα in Hebbian plasticity. Here, we addressed the relevance of APP in homeostatic synaptic plasticity using organotypic tissue cultures prepared from APP -/- mice of both sexes. In the absence of APP, dentate granule cells failed to strengthen their excitatory synapses homeostatically. Homeostatic plasticity is rescued by amyloid-β and not by APPsα, and it is neither observed in APP+/+ tissue treated with β- or γ-secretase inhibitors nor in synaptopodin-deficient cultures lacking the Ca2+-dependent molecular machinery of the spine apparatus. Together, these results suggest a role of APP processing via the amyloidogenic pathway in homeostatic synaptic plasticity, representing a function of relevance for brain physiology as well as for brain states associated with increased amyloid-β levels.
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Live Cell FRET Imaging Reveals Amyloid β-Peptide Oligomerization in Hippocampal Neurons. Int J Mol Sci 2021; 22:ijms22094530. [PMID: 33926107 PMCID: PMC8123703 DOI: 10.3390/ijms22094530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/22/2021] [Accepted: 04/24/2021] [Indexed: 11/17/2022] Open
Abstract
Amyloid β-peptide (Aβ) oligomerization is believed to contribute to the neuronal dysfunction in Alzheimer disease (AD). Despite decades of research, many details of Aβ oligomerization in neurons still need to be revealed. Förster resonance energy transfer (FRET) is a simple but effective way to study molecular interactions. Here, we used a confocal microscope with a sensitive Airyscan detector for FRET detection. By live cell FRET imaging, we detected Aβ42 oligomerization in primary neurons. The neurons were incubated with fluorescently labeled Aβ42 in the cell culture medium for 24 h. Aβ42 were internalized and oligomerized in the lysosomes/late endosomes in a concentration-dependent manner. Both the cellular uptake and intracellular oligomerization of Aβ42 were significantly higher than for Aβ40. These findings provide a better understanding of Aβ42 oligomerization in neurons.
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van Husen LS, Schedin-Weiss S, Trung MN, Kazmi MA, Winblad B, Sakmar TP, Elsässer SJ, Tjernberg LO. Dual Bioorthogonal Labeling of the Amyloid-β Protein Precursor Facilitates Simultaneous Visualization of the Protein and Its Cleavage Products. J Alzheimers Dis 2020; 72:537-548. [PMID: 31609694 PMCID: PMC6918917 DOI: 10.3233/jad-190898] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The amyloid-β protein precursor (AβPP) is critical in the pathophysiology of Alzheimer’s disease (AD), since two-step proteolytic processing of AβPP generates the neurotoxic amyloid-β peptide (Aβ). We developed a dual fluorescence labeling system to study the exact subcellular location of γ-secretase cleavage of AβPP. The C-terminal tail of AβPP was fluorescently labeled using a SNAP-tag, while the Aβ region of AβPP was fluorescently tagged with a dye at a genetically-encoded noncanonical amino acid (ncAA). The ncAA was introduced at specific positions in AβPP using a genetic code expansion strategy and afterwards, the reactive side-chain of the ncAA was coupled to the dye using a bioorthogonal labeling chemistry. In proof-of-concept experiments, HEK293T cells were transfected with plasmids containing engineered AβPP harboring an amber mutation and an amber codon suppression system with an evolved tRNA synthetase/tRNA pair and grown in the presence of a lysine-derived ncAA. Processing of the AβPP variants was validated with ELISA and immunoblotting, and seven AβPP mutants that showed similar cleavage pattern as wild-type AβPP were identified. The AβPP mutant was fluorescently labeled with 6-methyl-tetrazine-BDP-FL and TMR-Star at the ncAA and SNAP-tag, respectively. Using this approach, AβPP was fluorescently labeled at two sites in living cells with minimal background to allow monitoring of Aβ and C-terminal cleavage products simultaneously. The method described provides a powerful tool to label Aβ with minimal perturbations of its processing, thus enabling studies of the trafficking of the cleavage products of AβPP.
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Affiliation(s)
- Lea S van Husen
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Solna, Sweden
| | - Sophia Schedin-Weiss
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Solna, Sweden
| | - Minh Nguyen Trung
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany.,Institute of Chemistry, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Manija A Kazmi
- Laboratory of Chemical Biology & Signal Transduction, The Rockefeller University, New York, NY, USA
| | - Bengt Winblad
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Solna, Sweden.,Karolinska University Hospital, Theme Aging, Stockholm, Sweden
| | - Thomas P Sakmar
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Solna, Sweden.,Laboratory of Chemical Biology & Signal Transduction, The Rockefeller University, New York, NY, USA
| | - Simon J Elsässer
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Ming Wai Lau Centre for Reparative Medicine, Stockholm Node, Karolinska Institutet, Stockholm, Sweden
| | - Lars O Tjernberg
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Solna, Sweden
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9
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Hashimoto M, Yamazaki A, Ohno A, Kimura T, Winblad B, Tjernberg LO. A Fragment of S38AA is a Novel Plasma Biomarker of Alzheimer's Disease. J Alzheimers Dis 2020; 71:1163-1174. [PMID: 31524172 DOI: 10.3233/jad-190700] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease without a cure. The pathological process starts decades before clinical onset, and thus clinical trials of drugs aimed at treating AD should start at a presymptomatic stage. Therefore, it is critical to diagnose AD at an early stage. Tau, phosphorylated tau, and amyloid-β peptide (Aβ) in cerebrospinal fluid (CSF), and positron emission tomography (PET) imaging of Aβ or tau accumulation are supportive biomarkers for AD diagnosis, but there is no reliable presymptomatic diagnostic marker. Since CSF sampling is invasive, and PET imaging is expensive and available only at specialized centers, a reliable blood biomarker has long been sought for. Here we describe a novel extramembrane fragment from solute carrier family 38 member 10 (SLC38A10, S38AA) that we found to be decreased in pyramidal neurons in AD cases by proteomics and immunohistochemical analysis. We detected a S38AA fragment in CSF and found the levels to correlate with severity of AD and APOE genotype. Importantly, the plasma levels of the fragment also showed a significant correlation with Mini-Mental State Examination scores in AD. Moreover, plasma from other neurodegenerative disease was analyzed and the fragment was found to be increased specifically in AD. Interestingly, the fragment is detected in mouse, rat, and monkey, and increases in amyloid precursor protein transgenic mice as the AD-like pathology progresses. We propose that the S38AA fragment in plasma could be a novel quantitative diagnostic marker for AD and potentially a marker of disease progression in AD.
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Affiliation(s)
- Masakazu Hashimoto
- Drug Research Division, Sumitomo Dainippon Pharma Co., Ltd., Konohana-ku, Osaka, Japan
| | - Akira Yamazaki
- Drug Research Division, Sumitomo Dainippon Pharma Co., Ltd., Konohana-ku, Osaka, Japan
| | - Atsushi Ohno
- Drug Research Division, Sumitomo Dainippon Pharma Co., Ltd., Konohana-ku, Osaka, Japan
| | - Toru Kimura
- Drug Research Division, Sumitomo Dainippon Pharma Co., Ltd., Konohana-ku, Osaka, Japan
| | - Bengt Winblad
- Department of Neurobiology, Division for Neurogeriatrics, Care Sciences and Society (NVS), Karolinska Institutet, BioClinicum J9:20, Solna, Sweden.,Karolinska University Hospital, Theme Aging, Huddinge/Solna, Sweden
| | - Lars O Tjernberg
- Department of Neurobiology, Division for Neurogeriatrics, Care Sciences and Society (NVS), Karolinska Institutet, BioClinicum J9:20, Solna, Sweden
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10
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Del Carmen SLM, Laura GV, Leonardo OL, Bernabé RRG, Antonio MRM. Aβ40 Oligomers Promote Survival and Early Neuronal Differentiation of Dentate Gyrus-Isolated Precursor Cells Through Activation of the Akt Signaling Pathway. Neurotox Res 2020; 38:611-625. [PMID: 32623694 DOI: 10.1007/s12640-020-00253-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 06/13/2020] [Accepted: 06/29/2020] [Indexed: 11/26/2022]
Abstract
The amyloid beta-peptide (Aβ) is the low-abundance product of amyloid precursor protein (APP), which is produced lifelong in the healthy brain. The functional properties of Aβ40 and Aβ42 peptides have not been completely elucidated to date. Although, several studies suggest that these peptides have a number of neurotrophic and neurotoxic properties, respectively. Interestingly, low concentrations of Aβ40 and Aβ42 regulate synaptic plasticity and improve cognitive functions, whereas the accumulation of Aβ42, coupled with the effects of age, can cause dysregulation of synaptic function, as is shown in Alzheimer's disease. Additionally, several studies suggest that both peptides, Aβ40 and Aβ42, are involved in neurogenic processes; however, these results are still controversial. Moreover, existing data indicate a direct relationship between the physicochemical characteristics of the peptides and their effects. Herein, we evaluated the effect of Aβ40 oligomers on hippocampal precursor cells isolated from the dentate gyrus of adult female C57Bl6 mice (mADGPCs). To this end, mADGPCs were treated with nanomolar and micromolar range concentrations of oligomeric forms of Aβ40 for 24, 48, and 72 h to evaluate their effects on several events in the neurogenic process in vitro, including viability, proliferation, and early differentiation. The results indicate that Aβ40 favors mADGPC proliferation, survival, and neuronal differentiation following a mechanism that involves activation of the Akt signaling pathway. Thus, this study provides evidence about the positive effects of Aβ40 oligomers on the neurogenic process in adult mouse hippocampal precursor cells in vitro.
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Affiliation(s)
- Silva-Lucero María Del Carmen
- Laboratory of Neurogenesis, Division of Clinical Investigations, National Institute of Psychiatry "Ramón de la Fuente Muñiz", Calzada México-Xochimilco 101, 14370, Mexico City, Mexico
- Department of Molecular Biomedicine, Center for Research and Advanced Studies (CINVESTAV-IPN), Av. Instituto Politécnico Nacional 2508, 07360, Mexico City, Mexico
| | - Gómez-Virgilio Laura
- Laboratory of Neurogenesis, Division of Clinical Investigations, National Institute of Psychiatry "Ramón de la Fuente Muñiz", Calzada México-Xochimilco 101, 14370, Mexico City, Mexico
- Department of Molecular Biomedicine, Center for Research and Advanced Studies (CINVESTAV-IPN), Av. Instituto Politécnico Nacional 2508, 07360, Mexico City, Mexico
| | - Ortíz-López Leonardo
- Laboratory of Neurogenesis, Division of Clinical Investigations, National Institute of Psychiatry "Ramón de la Fuente Muñiz", Calzada México-Xochimilco 101, 14370, Mexico City, Mexico
| | - Ramírez-Rodríguez Gerardo Bernabé
- Laboratory of Neurogenesis, Division of Clinical Investigations, National Institute of Psychiatry "Ramón de la Fuente Muñiz", Calzada México-Xochimilco 101, 14370, Mexico City, Mexico.
| | - Meraz-Ríos Marco Antonio
- Department of Molecular Biomedicine, Center for Research and Advanced Studies (CINVESTAV-IPN), Av. Instituto Politécnico Nacional 2508, 07360, Mexico City, Mexico.
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11
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Sackmann C, Hallbeck M. Oligomeric amyloid-β induces early and widespread changes to the proteome in human iPSC-derived neurons. Sci Rep 2020; 10:6538. [PMID: 32300132 PMCID: PMC7162932 DOI: 10.1038/s41598-020-63398-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 03/23/2020] [Indexed: 01/05/2023] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia globally and is characterized by aberrant accumulations of amyloid-beta (Aβ) and tau proteins. Oligomeric forms of these proteins are believed to be most relevant to disease progression, with oligomeric amyloid-β (oAβ) particularly implicated in AD. oAβ pathology spreads among interconnected brain regions, but how oAβ induces pathology in these previously unaffected neurons requires further study. Here, we use well characterized iPSC-derived human neurons to study the early changes to the proteome and phosphoproteome after 24 h exposure to oAβ 1-42. Using nLC-MS/MS and label-free quantification, we identified several proteins that are differentially regulated in response to acute oAβ challenge. At this early timepoint, oAβ induced the decrease of TDP-43, heterogeneous nuclear ribonucleoproteins (hnRNPs), and coatomer complex I (COPI) proteins. Conversely, increases were observed in 20 S proteasome subunits and vesicle associated proteins VAMP1/2, as well as the differential phosphorylation of tau at serine 208. These changes show that there are widespread alterations to the neuronal proteome within 24 h of oAβ uptake, including proteins previously not shown to be related to neurodegeneration. This study provides new targets for the further study of early mediators of AD pathogenesis.
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Affiliation(s)
- Christopher Sackmann
- Department of Clinical Pathology and Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Martin Hallbeck
- Department of Clinical Pathology and Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.
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12
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Drummond E, Goñi F, Liu S, Prelli F, Scholtzova H, Wisniewski T. Potential Novel Approaches to Understand the Pathogenesis and Treat Alzheimer's Disease. J Alzheimers Dis 2019; 64:S299-S312. [PMID: 29562516 DOI: 10.3233/jad-179909] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
There is growing genetic and proteomic data highlighting the complexity of Alzheimer's disease (AD) pathogenesis. Greater use of unbiased "omics" approaches is being increasingly recognized as essential for the future development of effective AD research, that need to better reflect the multiple distinct pathway abnormalities that can drive AD pathology. The track record of success in AD clinical trials thus far has been very poor. In part, this high failure rate has been related to the premature translation of highly successful results in animal models that mirror only limited aspects of AD pathology to humans. We highlight our recent efforts to increase use of human tissue to gain a better understanding of the AD pathogenesis subtype variety and to develop several distinct therapeutic approaches tailored to address this diversity. These therapeutic approaches include the blocking of the Aβ/apoE interaction, stimulation of innate immunity, and the simultaneous blocking of Aβ/tau oligomer toxicity. We believe that future successful therapeutic approaches will need to be combined to better reflect the complexity of the abnormal pathways triggered in AD pathogenesis.
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Affiliation(s)
- Eleanor Drummond
- Department of Neurology, Center for Cognitive Neurology, NYU School of Medicine, New York, NY, USA
| | - Fernando Goñi
- Department of Neurology, Center for Cognitive Neurology, NYU School of Medicine, New York, NY, USA
| | - Shan Liu
- Department of Neurology, Center for Cognitive Neurology, NYU School of Medicine, New York, NY, USA
| | - Frances Prelli
- Department of Neurology, Center for Cognitive Neurology, NYU School of Medicine, New York, NY, USA
| | - Henrieta Scholtzova
- Department of Neurology, Center for Cognitive Neurology, NYU School of Medicine, New York, NY, USA
| | - Thomas Wisniewski
- Departments of Neurology, Pathology and Psychiatry, Center for Cognitive Neurology, NYU School of Medicine, New York, NY, USA
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13
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Toglia P, Demuro A, Mak DOD, Ullah G. Data-driven modeling of mitochondrial dysfunction in Alzheimer's disease. Cell Calcium 2018; 76:23-35. [PMID: 30248575 DOI: 10.1016/j.ceca.2018.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 09/02/2018] [Accepted: 09/03/2018] [Indexed: 02/06/2023]
Abstract
Intracellular accumulation of oligomeric forms of β amyloid (Aβ) are now believed to play a key role in the earliest phase of Alzheimer's disease (AD) as their rise correlates well with the early symptoms of the disease. Extensive evidence points to impaired neuronal Ca2+ homeostasis as a direct consequence of the intracellular Aβ oligomers. However, little is known about the downstream effects of the resulting Ca2+ rise on the many intracellular Ca2+-dependent pathways. Here we use multiscale modeling in conjunction with patch-clamp electrophysiology of single inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) and fluorescence imaging of whole-cell Ca2+ response, induced by exogenously applied intracellular Aβ42 oligomers to show that Aβ42 inflicts cytotoxicity by impairing mitochondrial function. Driven by patch-clamp experiments, we first model the kinetics of IP3R, which is then extended to build a model for the whole-cell Ca2+ signals. The whole-cell model is then fitted to fluorescence signals to quantify the overall Ca2+ release from the endoplasmic reticulum by intracellular Aβ42 oligomers through G-protein-mediated stimulation of IP3 production. The estimated IP3 concentration as a function of intracellular Aβ42 content together with the whole-cell model allows us to show that Aβ42 oligomers impair mitochondrial function through pathological Ca2+ uptake and the resulting reduced mitochondrial inner membrane potential, leading to an overall lower ATP and increased production of reactive oxygen species and H2O2. We further show that mitochondrial function can be restored by the addition of Ca2+ buffer EGTA, in accordance with the observed abrogation of Aβ42 cytotoxicity by EGTA in our live cells experiments.
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Affiliation(s)
- Patrick Toglia
- Department of Physics, University of South Florida, Tampa, FL 33620, USA
| | - Angelo Demuro
- Department of Neurobiology and Behavior and Physiology and Biophysics, University of California, Irvine, CA 92697, USA
| | - Don-On Daniel Mak
- Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ghanim Ullah
- Department of Physics, University of South Florida, Tampa, FL 33620, USA.
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14
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Yu Y, Jans DC, Winblad B, Tjernberg LO, Schedin-Weiss S. Neuronal Aβ42 is enriched in small vesicles at the presynaptic side of synapses. Life Sci Alliance 2018; 1:e201800028. [PMID: 30456353 PMCID: PMC6238618 DOI: 10.26508/lsa.201800028] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 06/01/2018] [Accepted: 06/01/2018] [Indexed: 12/26/2022] Open
Abstract
Super-resolution microscopy reveals that Aβ42 is mainly present at the presynaptic side of the synapse. The amyloid β-peptide (Aβ) is a physiological ubiquitously expressed peptide suggested to be involved in synaptic function, long-term potentiation, and memory function. The 42 amino acid-long variant (Aβ42) forms neurotoxic oligomers and amyloid plaques and plays a key role in the loss of synapses and other pathogenic events of Alzheimer disease. Still, the exact localization of Aβ42 in neurons and at synapses has not been reported. Here, we used super-resolution microscopy and show that Aβ42 was present in small vesicles in presynaptic compartments, but not in postsynaptic compartments, in the neurites of hippocampal neurons. Some of these vesicles appeared to lack synaptophysin, indicating that they differ from the synaptic vesicles responsible for neurotransmitter release. The Aβ42-containing vesicles existed in presynapses connected to stubby spines and mushroom spines, and were also present in immature presynapses. These vesicles were scarce in other parts of the neurites, where Aβ42 was instead present in large, around 200–600 nm, vesicular structures. Three-dimensional super-resolution microscopy confirmed that Aβ42 was present in the presynapse and absent in the postsynapse.
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Affiliation(s)
- Yang Yu
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Huddinge, Sweden
| | - Daniel C Jans
- Science for Life Laboratory, Department of Applied Physics, Royal Institute of Technology, Stockholm, Sweden
| | - Bengt Winblad
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Huddinge, Sweden
| | - Lars O Tjernberg
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Huddinge, Sweden
| | - Sophia Schedin-Weiss
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Huddinge, Sweden
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15
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Modulatory Effects of Fingolimod (FTY720) on the Expression of Sphingolipid Metabolism-Related Genes in an Animal Model of Alzheimer's Disease. Mol Neurobiol 2018; 56:174-185. [PMID: 29687345 PMCID: PMC6334734 DOI: 10.1007/s12035-018-1040-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 03/27/2018] [Indexed: 01/30/2023]
Abstract
Sphingolipid signaling disturbances correlate with Alzheimer's disease (AD) progression. We examined the influence of FTY720/fingolimod, a sphingosine analog and sphingosine-1-phosphate (S1P) receptor modulator, on the expression of sphingolipid metabolism and signaling genes in a mouse transgenic AD model. Our results demonstrated that AβPP (V717I) transgene led with age to reduced mRNA expression of S1P receptors (S1PRs), sphingosine kinase SPHK2, ceramide kinase CERK, and the anti-apoptotic Bcl2 in the cerebral cortex and hippocampus, suggesting a pro-apoptotic shift in 12-month old mice. These changes largely emulated alterations we observed in the human sporadic AD hippocampus: reduced SPHK1, SPHK2, CERK, S1PR1, and BCL2. We observed that the responses to FTY720 treatment were modified by age and notably differed between control (APP-) and AD transgenic (APP+) animals. AβPP (V717I)-expressing 12-month-old animals reacted to fingolimod with wide changes in the gene expression program in cortex and hippocampus, including increased pro-survival SPHKs and CERK. Moreover, BCL2 was elevated by FTY720 in the cortex at all ages (3, 6, 12 months) while in hippocampus this increase was observed at 12 months only. In APP- mice, fingolimod did not induce any significant mRNA changes at 12 months. Our results indicate significant effect of FTY720 on the age-dependent transcription of genes involved in sphingolipid metabolism and pro-survival signaling, suggesting its neuroprotective role in AD animal model.
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16
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Willén K, Sroka A, Takahashi RH, Gouras GK. Heterogeneous Association of Alzheimer's Disease-Linked Amyloid-β and Amyloid-β Protein Precursor with Synapses. J Alzheimers Dis 2018; 60:511-524. [PMID: 28869466 PMCID: PMC5611798 DOI: 10.3233/jad-170262] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Alzheimer’s disease (AD) is increasingly viewed as a disease of synapses. Loss of synapses correlates better with cognitive decline than amyloid plaques and neurofibrillary tangles, the hallmark neuropathological lesions of AD. Soluble forms of amyloid-β (Aβ) have emerged as mediators of synapse dysfunction. Aβ binds to, accumulates, and aggregates in synapses. However, the anatomical and neurotransmitter specificity of Aβ and the amyloid-β protein precursor (AβPP) in AD remain poorly understood. In addition, the relative roles of Aβ and AβPP in the development of AD, at pre- versus post-synaptic compartments and axons versus dendrites, respectively, remain unclear. Here we use immunogold electron microscopy and confocal microscopy to provide evidence for heterogeneity in the localization of Aβ/AβPP. We demonstrate that Aβ binds to a subset of synapses in cultured neurons, with preferential binding to glutamatergic compared to GABAergic neurons. We also highlight the challenge of defining pre- versus post-synaptic localization of this binding by confocal microscopy. Further, endogenous Aβ42 accumulates in both glutamatergic and GABAergic AβPP/PS1 transgenic primary neurons, but at varying levels. Moreover, upon knock-out of presenilin 1 or inhibition of γ-secretase AβPP C-terminal fragments accumulate both pre- and post-synaptically; however earlier pre-synaptically, consistent with a higher rate of AβPP processing in axons. A better understanding of the synaptic and anatomical selectivity of Aβ/AβPP in AD can be important for the development of more effective new therapies for this major disease of aging.
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Affiliation(s)
- Katarina Willén
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Agnieszka Sroka
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | | | - Gunnar K Gouras
- Department of Experimental Medical Science, Lund University, Lund, Sweden
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17
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A common mechanism of proteasome impairment by neurodegenerative disease-associated oligomers. Nat Commun 2018; 9:1097. [PMID: 29545515 PMCID: PMC5854577 DOI: 10.1038/s41467-018-03509-0] [Citation(s) in RCA: 198] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 02/20/2018] [Indexed: 12/21/2022] Open
Abstract
Protein accumulation and aggregation with a concomitant loss of proteostasis often contribute to neurodegenerative diseases, and the ubiquitin–proteasome system plays a major role in protein degradation and proteostasis. Here, we show that three different proteins from Alzheimer’s, Parkinson’s, and Huntington’s disease that misfold and oligomerize into a shared three-dimensional structure potently impair the proteasome. This study indicates that the shared conformation allows these oligomers to bind and inhibit the proteasome with low nanomolar affinity, impairing ubiquitin-dependent and ubiquitin-independent proteasome function in brain lysates. Detailed mechanistic analysis demonstrates that these oligomers inhibit the 20S proteasome through allosteric impairment of the substrate gate in the 20S core particle, preventing the 19S regulatory particle from injecting substrates into the degradation chamber. These results provide a novel molecular model for oligomer-driven impairment of proteasome function that is relevant to a variety of neurodegenerative diseases, irrespective of the specific misfolded protein that is involved. Disruption of the ubiquitin proteasome system (UPS) is often associated with neurodegenerative diseases. Here the authors demonstrate the existence of a general mechanism of proteasomal impairment triggered by a specific protein oligomer structure, irrespective of its protein constituent.
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18
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Schedin-Weiss S, Inoue M, Hromadkova L, Teranishi Y, Yamamoto NG, Wiehager B, Bogdanovic N, Winblad B, Sandebring-Matton A, Frykman S, Tjernberg LO. Monoamine oxidase B is elevated in Alzheimer disease neurons, is associated with γ-secretase and regulates neuronal amyloid β-peptide levels. ALZHEIMERS RESEARCH & THERAPY 2017; 9:57. [PMID: 28764767 PMCID: PMC5540560 DOI: 10.1186/s13195-017-0279-1] [Citation(s) in RCA: 144] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Accepted: 06/21/2017] [Indexed: 01/03/2023]
Abstract
Background Increased levels of the pathogenic amyloid β-peptide (Aβ), released from its precursor by the transmembrane protease γ-secretase, are found in Alzheimer disease (AD) brains. Interestingly, monoamine oxidase B (MAO-B) activity is also increased in AD brain, but its role in AD pathogenesis is not known. Recent neuroimaging studies have shown that the increased MAO-B expression in AD brain starts several years before the onset of the disease. Here, we show a potential connection between MAO-B, γ-secretase and Aβ in neurons. Methods MAO-B immunohistochemistry was performed on postmortem human brain. Affinity purification of γ-secretase followed by mass spectrometry was used for unbiased identification of γ-secretase-associated proteins. The association of MAO-B with γ-secretase was studied by coimmunoprecipitation from brain homogenate, and by in-situ proximity ligation assay (PLA) in neurons as well as mouse and human brain sections. The effect of MAO-B on Aβ production and Notch processing in cell cultures was analyzed by siRNA silencing or overexpression experiments followed by ELISA, western blot or FRET analysis. Methodology for measuring relative intraneuronal MAO-B and Aβ42 levels in single cells was developed by combining immunocytochemistry and confocal microscopy with quantitative image analysis. Results Immunohistochemistry revealed MAO-B staining in neurons in the frontal cortex, hippocampus CA1 and entorhinal cortex in postmortem human brain. Interestingly, the neuronal staining intensity was higher in AD brain than in control brain in these regions. Mass spectrometric data from affinity purified γ-secretase suggested that MAO-B is a γ-secretase-associated protein, which was confirmed by immunoprecipitation and PLA, and a neuronal location of the interaction was shown. Strikingly, intraneuronal Aβ42 levels correlated with MAO-B levels, and siRNA silencing of MAO-B resulted in significantly reduced levels of intraneuronal Aβ42. Furthermore, overexpression of MAO-B enhanced Aβ production. Conclusions This study shows that MAO-B levels are increased not only in astrocytes but also in pyramidal neurons in AD brain. The study also suggests that MAO-B regulates Aβ production in neurons via γ-secretase and thereby provides a key to understanding the relationship between MAO-B and AD pathogenesis. Potentially, the γ-secretase/MAO-B association may be a target for reducing Aβ levels using protein–protein interaction breakers. Electronic supplementary material The online version of this article (doi:10.1186/s13195-017-0279-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sophia Schedin-Weiss
- Karolinska Institutet, Department NVS, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden.
| | - Mitsuhiro Inoue
- Karolinska Institutet, Department NVS, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden.,Present address: Dainippon Sumitomo Pharma Co., Ltd, Drug Development Research Laboratories, Osaka, Japan
| | - Lenka Hromadkova
- National Institute of Mental Health, Klecany, Czech Republic.,Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Yasuhiro Teranishi
- Karolinska Institutet, Department NVS, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden.,Present address: Dainippon Sumitomo Pharma Co., Ltd, Drug Development Research Laboratories, Osaka, Japan
| | - Natsuko Goto Yamamoto
- Karolinska Institutet, Department NVS, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden.,Present address: Dainippon Sumitomo Pharma Co., Ltd, Drug Development Research Laboratories, Osaka, Japan
| | - Birgitta Wiehager
- Karolinska Institutet, Department NVS, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden
| | - Nenad Bogdanovic
- Department of Geriatric Medicine, University in Oslo, Memory Clinic, Oslo University Hospital, Oslo, Norway
| | - Bengt Winblad
- Karolinska Institutet, Department NVS, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden
| | - Anna Sandebring-Matton
- Karolinska Institutet, Department NVS, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden
| | - Susanne Frykman
- Karolinska Institutet, Department NVS, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden
| | - Lars O Tjernberg
- Karolinska Institutet, Department NVS, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden
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Localized Proteomics of Individual Neurons Isolated from Formalin-Fixed, Paraffin-Embedded Tissue Sections Using Laser Capture Microdissection. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/978-1-4939-7119-0_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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20
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Proteomic differences in amyloid plaques in rapidly progressive and sporadic Alzheimer's disease. Acta Neuropathol 2017; 133:933-954. [PMID: 28258398 DOI: 10.1007/s00401-017-1691-0] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 02/22/2017] [Accepted: 02/26/2017] [Indexed: 12/16/2022]
Abstract
Rapidly progressive Alzheimer's disease (rpAD) is a particularly aggressive form of Alzheimer's disease, with a median survival time of 7-10 months after diagnosis. Why these patients have such a rapid progression of Alzheimer's disease is currently unknown. To further understand pathological differences between rpAD and typical sporadic Alzheimer's disease (sAD) we used localized proteomics to analyze the protein differences in amyloid plaques in rpAD and sAD. Label-free quantitative LC-MS/MS was performed on amyloid plaques microdissected from rpAD and sAD patients (n = 22 for each patient group) and protein expression differences were quantified. On average, 913 ± 30 (mean ± SEM) proteins were quantified in plaques from each patient and 279 of these proteins were consistently found in plaques from every patient. We found significant differences in protein composition between rpAD and sAD plaques. We found that rpAD plaques contained significantly higher levels of neuronal proteins (p = 0.0017) and significantly lower levels of astrocytic proteins (p = 1.08 × 10-6). Unexpectedly, cumulative protein differences in rpAD plaques did not suggest accelerated typical sAD. Plaques from patients with rpAD were particularly abundant in synaptic proteins, especially those involved in synaptic vesicle release, highlighting the potential importance of synaptic dysfunction in the accelerated development of plaque pathology in rpAD. Combined, our data provide new direct evidence that amyloid plaques do not all have the same protein composition and that the proteomic differences in plaques could provide important insight into the factors that contribute to plaque development. The cumulative protein differences in rpAD plaques suggest rpAD may be a novel subtype of Alzheimer's disease.
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21
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Xia M, Yang L, Sun G, Qi S, Li B. Mechanism of depression as a risk factor in the development of Alzheimer's disease: the function of AQP4 and the glymphatic system. Psychopharmacology (Berl) 2017; 234:365-379. [PMID: 27837334 DOI: 10.1007/s00213-016-4473-9] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 10/23/2016] [Indexed: 12/19/2022]
Abstract
BACKGROUND Many studies have indicated that a history of depression increases the risk of developing Alzheimer's disease (AD); however, the potential pathogenestic mechanism by which depression functions as a high risk factor for AD remains unknown. Recently, a "cerebral lymphatic system" referred to as "glymphatic system" has been demonstrated to be responsible for neuronal extracellular waste protein clearance via a paravascular pathway. However, the function of glymphatic pathway has not been determined in depressive disorders. METHODS The present study used an animal model of chronic unpredictable mild stress (CUMS) to determine the function of glymphatic pathway by using fluorescence tracers. Immunohistochemistry was used to assess the accumulation of endogenous mouse and exogenous human amyloid beta 42 (Aβ42) in CUMS-treated mice with or without treatment with antidepressant fluoxetine. FINDINGS Glymphatic pathway circulation was impaired in mice treated with CUMS; moreover, glymphatic pathway dysfunction suppressed Aβ42 metabolism, because the accumulation of endogenous and exogenous Aβ42 was increased in the brains of the CUMS-treated mice. However, treatment with fluoxetine reversed these destructive effects of CUMS on glymphatic system. In anhedonic mice, the expression of the water channel aquaporin 4 (AQP4), a factor in glymphatic pathway dysfunction, was down-regulated in cortex and hippocampus. CONCLUSION The dysfunction of glymphatic system suggested why a history of depression may be a strong risk factor for AD in anhedonic mice. We hope our study will contribute to an understanding of the risk mechanism of depressive disorder in the development of AD and the mechanisms of antidepressant therapies in AD.
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Affiliation(s)
- Maosheng Xia
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, Shenyang, No. 77, Puhe Street, Shenbei District, Shenyang, 110177, People's Republic of China.,Department of Orthopaedics, The First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Li Yang
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, Shenyang, No. 77, Puhe Street, Shenbei District, Shenyang, 110177, People's Republic of China
| | - Guangfeng Sun
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, Shenyang, No. 77, Puhe Street, Shenbei District, Shenyang, 110177, People's Republic of China.,Department of Orthopaedics, The First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Shuang Qi
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, Shenyang, No. 77, Puhe Street, Shenbei District, Shenyang, 110177, People's Republic of China.,Department of Orthopaedics, The First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Baoman Li
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, Shenyang, No. 77, Puhe Street, Shenbei District, Shenyang, 110177, People's Republic of China. .,Department of Orthopaedics, The First Hospital of China Medical University, Shenyang, People's Republic of China.
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22
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Maturation and processing of the amyloid precursor protein is regulated by the potassium/sodium hyperpolarization-activated cyclic nucleotide-gated ion channel 2 (HCN2). Biochem Biophys Res Commun 2017; 483:352-358. [DOI: 10.1016/j.bbrc.2016.12.140] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 12/21/2016] [Indexed: 01/15/2023]
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23
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Wilkins HM, Swerdlow RH. Amyloid precursor protein processing and bioenergetics. Brain Res Bull 2016; 133:71-79. [PMID: 27545490 DOI: 10.1016/j.brainresbull.2016.08.009] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 08/15/2016] [Accepted: 08/17/2016] [Indexed: 02/08/2023]
Abstract
The processing of amyloid precursor protein (APP) to amyloid beta (Aβ) is of great interest to the Alzheimer's disease (AD) field. Decades of research define how APP is altered to form Aβ, and how Aβ generates oligomers, protofibrils, and fibrils. Numerous signaling pathways and changes in cell physiology are known to influence APP processing. Existing data additionally indicate a relationship exists between mitochondria, bioenergetics, and APP processing. Here, we review data that address whether mitochondrial function and bioenergetics modify APP processing and Aβ production.
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Affiliation(s)
- Heather M Wilkins
- Department of Neurology University of Kansas Medical Center, Kansas City, KS, USA; University of Kansas Alzheimer's Disease Center, Kansas City, KS, USA
| | - Russell H Swerdlow
- Department of Neurology University of Kansas Medical Center, Kansas City, KS, USA; University of Kansas Alzheimer's Disease Center, Kansas City, KS, USA; Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA; Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS USA.
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Schedin-Weiss S, Caesar I, Winblad B, Blom H, Tjernberg LO. Super-resolution microscopy reveals γ-secretase at both sides of the neuronal synapse. Acta Neuropathol Commun 2016; 4:29. [PMID: 27036709 PMCID: PMC4818506 DOI: 10.1186/s40478-016-0296-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 03/08/2016] [Indexed: 01/08/2023] Open
Abstract
The transmembrane protein assembly γ-secretase is a key protease in regulated intramembrane processing (RIP) of around 100 type-1 transmembrane proteins. Importantly, it has a pathological role in Alzheimer disease (AD) as it generates the neurotoxic amyloid β-peptide from the amyloid precursor protein (APP). Studies on γ-secretase location are therefore crucial both from a biological and a therapeutic perspective. Despite several years of efforts in many laboratories, it is not clear where in the neuron γ-secretase exerts it’s activities. Technical challenges include the fact that the active enzyme contains four protein components and that most subcellular compartments cannot be spatially resolved by traditional light microscopy. Here, we have used a powerful combination of the two nanoscopy techniques STORM and STED microscopy to visualize the location of γ-secretase in neurons using an active-site specific probe, with a focus on the synapse. We show that γ-secretase is present in both the pre-and postsynaptic compartments. We further show that the enzyme is enriched very close to the synaptic cleft in the postsynaptic membrane, as well as to NMDA receptors, demonstrating that γ-secretase is present in the postsynaptic plasma membrane. Importantly, the expression of γ-secretase increased in the pre- and postsynaptic compartments with the size of the synapse, suggesting a correlation between γ-secretase activity and synapse maturation. Thus, our data shows the synaptic location with high precision in three dimensions and settles the long-lasting debate on the synaptic location of γ-secretase.
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Huang JZ, Wu J, Xiang S, Sheng S, Jiang Y, Yang Z, Hua F. Catalpol preserves neural function and attenuates the pathology of Alzheimer's disease in mice. Mol Med Rep 2015; 13:491-6. [PMID: 26531891 DOI: 10.3892/mmr.2015.4496] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Accepted: 10/02/2015] [Indexed: 11/06/2022] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia and there currently are no effective treatment strategies available. Catalpol is an iridoid glucoside, and large quantities can be isolated from the genus Rehmannia (Orobanchaceae). The present study assessed whether catalpol had any protective effects against Alzheimer's disease using a murine model. Reactive oxygen species (ROS)-associated enzymes as well as soluble Aβ40 and Aβ42 were detected using kits. Thioflavin‑S staining was performed to detect senile plaques and reverse-transcription quantitative polymerase chain reaction was used to assess iroquois homeobox protein 3 (IRX3) and obesity‑associated genes, while western blot analysis was used for β‑secretase 1 (BACE1), insulin‑degrading enzyme (IDE) and neprilysin (NEP) detection. The Morris water maze was used to detect the learning ability and spatial memory. The results revealed that catalpol was able to reduce the oxidative stress in the cerebral cortex by regulating the activities and concentration of ROS‑associated enzymes superoxide dismutase, glutathione peroxidase and catalase, however not malondialdehyde. Catalpol was also identified to be able to reduce the levels of soluble Aβ40 and Aβ42 in the cerebral cortex and thus inhibit the formation of senile plaques. These effects were observed to be regulated by IDE, however not by BACE1 or NEP. It is suggested that catalpol is not capable of directly regulating the expression of IRX3 and obesity‑associated genes. Subsequent to the treatment with catalpol, impairments in learning and memory were also observed to be relieved using the Morris water maze test. The results of the present study indicate that catalpol may be a potential drug for the treatment of neurodegenerative diseases such as AD.
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Affiliation(s)
- Jin-Zhong Huang
- Department of Neurology, The Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu 213000, P.R. China
| | - Jian Wu
- Department of Neurology, The Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu 213000, P.R. China
| | - Shoukui Xiang
- Department of Endocrinology, The Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu 213000, P.R. China
| | - Shiying Sheng
- Department of Neurology, The Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu 213000, P.R. China
| | - Ying Jiang
- Department of Neurology, The Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu 213000, P.R. China
| | - Zhilong Yang
- Department of Neurology, The Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu 213000, P.R. China
| | - Fei Hua
- Department of Endocrinology, The Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu 213000, P.R. China
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Proteomic analysis of neurons microdissected from formalin-fixed, paraffin-embedded Alzheimer's disease brain tissue. Sci Rep 2015; 5:15456. [PMID: 26487484 PMCID: PMC4614382 DOI: 10.1038/srep15456] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 09/25/2015] [Indexed: 12/22/2022] Open
Abstract
The vast majority of human tissue specimens are formalin-fixed, paraffin embedded (FFPE) archival samples, making this type of tissue a potential gold mine for medical research. It is now accepted that proteomics can be done using FFPE tissue and can generate similar results as snap-frozen tissue. However, the current methodology requires a large amount of starting protein, limiting the questions that can be answered in these types of proteomics studies and making cell-type specific proteomics studies difficult. Cell-type specific proteomics has the potential to greatly enhance understanding of cell functioning in both normal and disease states. Therefore, here we describe a new method that allows localized proteomics on individual cell populations isolated from FFPE tissue sections using laser capture microdissection. To demonstrate this technique we microdissected neurons from archived tissue blocks of the temporal cortex from patients with Alzheimer’s disease. Using this method we identified over 400 proteins in microdissected neurons; on average 78% that were neuronal and 50% that were associated with Alzheimer’s disease. Therefore, this technique is able to provide accurate and meaningful data and has great potential for any future study that wishes to perform localized proteomics using very small amounts of archived FFPE tissue.
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The workflow from post-mortem human brain sampling to cell microdissection: a Brain Net Europe study. J Neural Transm (Vienna) 2015; 122:975-91. [DOI: 10.1007/s00702-015-1378-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 02/04/2015] [Indexed: 11/25/2022]
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Sérrière S, Tauber C, Vercouillie J, Mothes C, Pruckner C, Guilloteau D, Kassiou M, Doméné A, Garreau L, Page G, Chalon S. Amyloid load and translocator protein 18 kDa in APPswePS1-dE9 mice: a longitudinal study. Neurobiol Aging 2015; 36:1639-1652. [PMID: 25680265 DOI: 10.1016/j.neurobiolaging.2014.11.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 11/03/2014] [Accepted: 11/25/2014] [Indexed: 12/16/2022]
Abstract
We studied concomitantly the level of neuroinflammation and β-amyloid (Aβ) load in the APPswePS1dE9 transgenic mouse model of Alzheimer's disease using positron emission tomography. The translocator protein 18 kDa (TSPO) tracer [(18)F]DPA-714 was used to measure neuroinflammation and [(18)F]AV-45 for Aβ load in mice at 6, 9, 12, 15, and 19 months of age. At 19 months, we also analyzed the neuroinflammatory and neuroanatomic status of mice brains. The main affected brain areas were the cortex and hippocampus, with a concomitant progression of neuroinflammation with increased amyloid burden. At 19 months, no increase in TSPO binding was observed in the cerebellum; immunostaining revealed W0-2-positive plaques, indicating that the amyloid deposits seemed not stimulate inflammation. This finding was in agreement with the observed level of microglia and astrocytes staining. Our findings provide a better understanding of the relationships between neuroinflammation and plaque accumulation in the course of the disease in this mouse model. The monitoring of both processes should be of value to validate potential therapeutic approaches.
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Affiliation(s)
- Sophie Sérrière
- UMR Inserm U930, Université François-Rabelais de Tours, Tours, France
| | - Clovis Tauber
- UMR Inserm U930, Université François-Rabelais de Tours, Tours, France
| | | | | | | | - Denis Guilloteau
- UMR Inserm U930, Université François-Rabelais de Tours, Tours, France; CHRU de Tours, Tours, France
| | - Michael Kassiou
- School of Chemistry and Faculty of Health Sciences, University of Sydney, Sydney, Australia
| | - Aurélie Doméné
- UMR Inserm U930, Université François-Rabelais de Tours, Tours, France
| | - Lucette Garreau
- UMR Inserm U930, Université François-Rabelais de Tours, Tours, France
| | - Guylène Page
- EA 3808 CiMoTheMA, Université de Poitiers, Poitiers, France
| | - Sylvie Chalon
- UMR Inserm U930, Université François-Rabelais de Tours, Tours, France.
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Intracellular accumulation of amyloid-β (Aβ) protein plays a major role in Aβ-induced alterations of glutamatergic synaptic transmission and plasticity. J Neurosci 2014; 34:12893-903. [PMID: 25232124 DOI: 10.1523/jneurosci.1201-14.2014] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Intracellular accumulation of amyloid-β (Aβ) protein has been proposed as an early event in AD pathogenesis. In patients with mild cognitive impairment, intraneuronal Aβ immunoreactivity was found especially in brain regions critically involved in the cognitive deficits of AD. Although a large body of evidence demonstrates that Aβ42 accumulates intraneuronally ((in)Aβ), the action and the role of Aβ42 buildup on synaptic function have been poorly investigated. Here, we demonstrate that basal synaptic transmission and LTP were markedly depressed following Aβ42 injection into the neuron through the patch pipette. Control experiments performed with the reverse peptide (Aβ42-1) allowed us to exclude that the effects of (in)Aβ depended on changes in oncotic pressure. To further investigate (in)Aβ synaptotoxicity we used an Aβ variant harboring oxidized methionine in position 35 that does not cross the neuronal plasma membrane and is not uploaded from the extracellular space. This Aβ42 variant had no effects on synaptic transmission and plasticity when applied extracellularly, but induced synaptic depression and LTP inhibition after patch-pipette dialysis. Finally, the injection of an antibody raised against human Aβ42 (6E10) in CA1 pyramidal neurons of mouse hippocampal brain slices and autaptic microcultures did not, per se, significantly affect LTP and basal synaptic transmission, but it protected against the toxic effects of extracellular Aβ42. Collectively, these findings suggest that Aβ42-induced impairment of glutamatergic synaptic function depends on its internalization and intracellular accumulation thus paving the way to a systemic proteomic analysis of intracellular targets/partners of Aβ42.
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Iulita MF, Allard S, Richter L, Munter LM, Ducatenzeiler A, Weise C, Do Carmo S, Klein WL, Multhaup G, Cuello AC. Intracellular Aβ pathology and early cognitive impairments in a transgenic rat overexpressing human amyloid precursor protein: a multidimensional study. Acta Neuropathol Commun 2014; 2:61. [PMID: 24903713 PMCID: PMC4229908 DOI: 10.1186/2051-5960-2-61] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 05/07/2014] [Indexed: 01/09/2023] Open
Abstract
Numerous studies have implicated the abnormal accumulation of intraneuronal amyloid-β (Aβ) as an important contributor to Alzheimer's disease (AD) pathology, capable of triggering neuroinflammation, tau hyperphosphorylation and cognitive deficits. However, the occurrence and pathological relevance of intracellular Aβ remain a matter of controversial debate. In this study, we have used a multidimensional approach including high-magnification and super-resolution microscopy, cerebro-spinal fluid (CSF) mass spectrometry analysis and ELISA to investigate the Aβ pathology and its associated cognitive impairments, in a novel transgenic rat model overexpressing human APP. Our microscopy studies with quantitative co-localization analysis revealed the presence of intraneuronal Aβ in transgenic rats, with an immunological signal that was clearly distinguished from that of the amyloid precursor protein (APP) and its C-terminal fragments (CTFs). The early intraneuronal pathology was accompanied by a significant elevation of soluble Aβ42 peptides that paralleled the presence and progression of early cognitive deficits, several months prior to amyloid plaque deposition. Aβ38, Aβ39, Aβ40 and Aβ42 peptides were detected in the rat CSF by MALDI-MS analysis even at the plaque-free stages; suggesting that a combination of intracellular and soluble extracellular Aβ may be responsible for impairing cognition at early time points. Taken together, our results demonstrate that the intraneuronal development of AD-like amyloid pathology includes a mixture of molecular species (Aβ, APP and CTFs) of which a considerable component is Aβ; and that the early presence of these species within neurons has deleterious effects in the CNS, even before the development of full-blown AD-like pathology.
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Affiliation(s)
- M Florencia Iulita
- />Department of Pharmacology and Therapeutics, McGill University, 3655 Sir-William-Osler Promenade, Room 1210, Montreal, Quebec Canada
| | - Simon Allard
- />Department of Pharmacology and Therapeutics, McGill University, 3655 Sir-William-Osler Promenade, Room 1210, Montreal, Quebec Canada
| | - Luise Richter
- />Department of Pharmacology and Therapeutics, McGill University, 3655 Sir-William-Osler Promenade, Room 1210, Montreal, Quebec Canada
| | - Lisa-Marie Munter
- />Department of Pharmacology and Therapeutics, McGill University, 3655 Sir-William-Osler Promenade, Room 1210, Montreal, Quebec Canada
| | - Adriana Ducatenzeiler
- />Department of Pharmacology and Therapeutics, McGill University, 3655 Sir-William-Osler Promenade, Room 1210, Montreal, Quebec Canada
| | - Christoph Weise
- />Intitutes of Chemistry and Biochemistry, Freie Universität, Berlin, Germany
| | - Sonia Do Carmo
- />Department of Pharmacology and Therapeutics, McGill University, 3655 Sir-William-Osler Promenade, Room 1210, Montreal, Quebec Canada
| | - William L Klein
- />Cognitive Neurology and Alzheimer’s Disease Center, Northwestern University Institute for Neuroscience, Chicago, USA
| | - Gerhard Multhaup
- />Department of Pharmacology and Therapeutics, McGill University, 3655 Sir-William-Osler Promenade, Room 1210, Montreal, Quebec Canada
| | - A Claudio Cuello
- />Department of Pharmacology and Therapeutics, McGill University, 3655 Sir-William-Osler Promenade, Room 1210, Montreal, Quebec Canada
- />Department of Anatomy and Cell Biology, McGill University, Montreal, Canada
- />Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
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Wanngren J, Lara P, Ojemalm K, Maioli S, Moradi N, Chen L, Tjernberg LO, Lundkvist J, Nilsson I, Karlström H. Changed membrane integration and catalytic site conformation are two mechanisms behind the increased Aβ42/Aβ40 ratio by presenilin 1 familial Alzheimer-linked mutations. FEBS Open Bio 2014; 4:393-406. [PMID: 24918054 PMCID: PMC4050182 DOI: 10.1016/j.fob.2014.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 04/16/2014] [Accepted: 04/17/2014] [Indexed: 01/11/2023] Open
Abstract
Familial Alzheimer disease (FAD) mutations affect presenilin membrane integration. The transmembrane domains around the catalytic site are vulnerable to changes. All FAD mutations cause changes in the active site of the γ-secretase complex. The FAD mutants lead to a complex processing pattern of the amyloid precursor protein.
The enzyme complex γ-secretase generates amyloid β-peptide (Aβ), a 37–43-residue peptide associated with Alzheimer disease (AD). Mutations in presenilin 1 (PS1), the catalytical subunit of γ-secretase, result in familial AD (FAD). A unifying theme among FAD mutations is an alteration in the ratio Aβ species produced (the Aβ42/Aβ40 ratio), but the molecular mechanisms responsible remain elusive. In this report we have studied the impact of several different PS1 FAD mutations on the integration of selected PS1 transmembrane domains and on PS1 active site conformation, and whether any effects translate to a particular amyloid precursor protein (APP) processing phenotype. Most mutations studied caused an increase in the Aβ42/Aβ40 ratio, but via different mechanisms. The mutations that caused a particular large increase in the Aβ42/Aβ40 ratio did also display an impaired APP intracellular domain (AICD) formation and a lower total Aβ production. Interestingly, seven mutations close to the catalytic site caused a severely impaired integration of proximal transmembrane/hydrophobic sequences into the membrane. This structural defect did not correlate to a particular APP processing phenotype. Six selected FAD mutations, all of which exhibited different APP processing profiles and impact on PS1 transmembrane domain integration, were found to display an altered active site conformation. Combined, our data suggest that FAD mutations affect the PS1 structure and active site differently, resulting in several complex APP processing phenotypes, where the most aggressive mutations in terms of increased Aβ42/Aβ40 ratio are associated with a decrease in total γ-secretase activity.
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Key Words
- AD, Alzheimer disease
- AICD, amyloid precursor protein intracellular domain
- APP, amyloid precursor protein
- Alzheimer disease
- Amyloid β-peptide
- Aβ, amyloid-β peptide
- BD8, blastocyst-derived embryonic stem cells
- Bis-Tris, 2-(bis(2-hydroxyethyl)amino)-2-(hydroxymethyl)propane-1,3-diol
- CHAPSO, 3-[(3-cholamidopropyl)dimethylammonio]-2-hydroxy-1-propanesulfonic acid
- CRM, column-washed dog pancreas rough microsomes
- CTF, C-terminal fragment
- ER, endoplasmic reticulum
- Endo H, endoglycosidase H
- FAD, familial AD
- FLIM/FRET, Fluorescence Lifetime Imaging/ Fluorescence Resonance Energy Transfer
- GCB, γ-secretase inhibitor coupled to biotin
- GVP, Gal4VP16
- Lep, leader peptidase
- MGD, minimal glycosylation distance
- MSD, Meso Scale Discovery
- Membrane integration
- NTF, N-terminal fragment
- PS, presenilin
- Protein structure
- RM, rough microsomes
- TMD, transmembrane domains
- WT, wild type
- γ-Secretase
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Affiliation(s)
- Johanna Wanngren
- Department of NVS, Center for Alzheimer Research, Karolinska Institutet, Stockholm, Sweden
| | - Patricia Lara
- Department of Biochemistry & Biophysics, Stockholm University, Stockholm, Sweden
| | - Karin Ojemalm
- Department of Biochemistry & Biophysics, Stockholm University, Stockholm, Sweden
| | - Silvia Maioli
- Department of NVS, Center for Alzheimer Research, Karolinska Institutet, Stockholm, Sweden
| | - Nasim Moradi
- Department of Biochemistry & Biophysics, Stockholm University, Stockholm, Sweden
| | - Lu Chen
- Department of Biochemistry & Biophysics, Stockholm University, Stockholm, Sweden
| | - Lars O Tjernberg
- Department of NVS, Center for Alzheimer Research, Karolinska Institutet, Stockholm, Sweden
| | | | - IngMarie Nilsson
- Department of Biochemistry & Biophysics, Stockholm University, Stockholm, Sweden
| | - Helena Karlström
- Department of NVS, Center for Alzheimer Research, Karolinska Institutet, Stockholm, Sweden
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Kuwabara Y, Ishizeki M, Watamura N, Toba J, Yoshii A, Inoue T, Ohshima T. Impairments of long-term depression induction and motor coordination precede Aβ accumulation in the cerebellum of APPswe/PS1dE9 double transgenic mice. J Neurochem 2014; 130:432-43. [DOI: 10.1111/jnc.12728] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Revised: 03/23/2014] [Accepted: 03/27/2014] [Indexed: 12/22/2022]
Affiliation(s)
- Yuki Kuwabara
- Laboratory for Molecular Brain Science; Department of Life Science and Medical Bioscience; Waseda University; Tokyo Japan
| | - Masato Ishizeki
- Laboratory of Neurophysiology; Department of Life Science and Medical Bioscience; Waseda University; Tokyo Japan
| | - Naoto Watamura
- Laboratory for Molecular Brain Science; Department of Life Science and Medical Bioscience; Waseda University; Tokyo Japan
| | - Junya Toba
- Laboratory for Molecular Brain Science; Department of Life Science and Medical Bioscience; Waseda University; Tokyo Japan
| | - Aya Yoshii
- Laboratory for Molecular Brain Science; Department of Life Science and Medical Bioscience; Waseda University; Tokyo Japan
| | - Takafumi Inoue
- Laboratory of Neurophysiology; Department of Life Science and Medical Bioscience; Waseda University; Tokyo Japan
| | - Toshio Ohshima
- Laboratory for Molecular Brain Science; Department of Life Science and Medical Bioscience; Waseda University; Tokyo Japan
- Laboratory for Developmental Neurobiology; RIKEN Brain Science Institute; Wako Saitama Japan
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Lundgren JL, Ahmed S, Winblad B, Gouras GK, Tjernberg LO, Frykman S. Activity-independent release of the amyloid β-peptide from rat brain nerve terminals. Neurosci Lett 2014; 566:125-30. [PMID: 24602978 DOI: 10.1016/j.neulet.2014.02.050] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 02/10/2014] [Accepted: 02/23/2014] [Indexed: 01/21/2023]
Abstract
Synaptic degeneration is one of the earliest hallmarks of Alzheimer disease. The molecular mechanism underlying this degeneration is not fully elucidated but one key player appears to be the synaptotoxic amyloid β-peptide (Aβ). The exact localization of the production of Aβ and the mechanisms whereby Aβ is released remain elusive. We have earlier shown that Aβ can be produced in crude synaptic vesicle fractions and it has been reported that increased synaptic activity results in increased secreted but decreased intracellular Aβ levels. Therefore, we considered whether Aβ could be produced in synaptic vesicles and/or released through the same mechanisms as neurotransmitters in synaptic vesicle exocytosis. Small amounts of Aβ were found to be produced in pure synaptic vesicle preparations. We also studied the release of glutamate and Aβ from rat cortical nerve terminals (synaptosomes). We found that large amounts of Aβ were secreted from non-stimulated synaptosomes, from which glutamate was not released. On the contrary, we could not detect any differences in Aβ release between non-stimulated synaptosomes and synaptosomes stimulated with KCl or 4-aminopyridine, whereas glutamate release was readily inducible in this system. To conclude, our results indicate that the major release mechanism of Aβ from isolated nerve terminals differs from the synaptic release of glutamate and that the activity-dependent increase of secreted Aβ, reported by several groups using intact cells, is likely dependent on post-synaptic events, trafficking and/or protein synthesis mechanisms.
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Affiliation(s)
- Jolanta L Lundgren
- Karolinska Institutet, Department of Neurobiology, Care Science and Society, Center for Alzheimer Research, Novum level 5, 141 86 Stockholm, Sweden
| | - Saheeb Ahmed
- European Neuroscience Institute, Grisebachstrasse 5, 37077 Göttingen, Germany
| | - Bengt Winblad
- Karolinska Institutet, Department of Neurobiology, Care Science and Society, Center for Alzheimer Research, Novum level 5, 141 86 Stockholm, Sweden
| | - Gunnar K Gouras
- Lund University, Department of Experimental Medical Science, Experimental Dementia Research Unit, Sölveg 19, BMC B12, 221 84 Lund, Sweden
| | - Lars O Tjernberg
- Karolinska Institutet, Department of Neurobiology, Care Science and Society, Center for Alzheimer Research, Novum level 5, 141 86 Stockholm, Sweden
| | - Susanne Frykman
- Karolinska Institutet, Department of Neurobiology, Care Science and Society, Center for Alzheimer Research, Novum level 5, 141 86 Stockholm, Sweden.
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Baldassarro VA, Lizzo G, Paradisi M, Fernández M, Giardino L, Calzà L. Neural stem cells isolated from amyloid precursor protein-mutated mice for drug discovery. World J Stem Cells 2013; 5:229-237. [PMID: 24179610 PMCID: PMC3812526 DOI: 10.4252/wjsc.v5.i4.229] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 08/07/2013] [Accepted: 10/18/2013] [Indexed: 02/06/2023] Open
Abstract
AIM: To develop an in vitro model based on neural stem cells derived from transgenic animals, to be used in the study of pathological mechanisms of Alzheimer’s disease and for testing new molecules.
METHODS: Neural stem cells (NSCs) were isolated from the subventricular zone of Wild type (Wt) and Tg2576 mice. Primary and secondary neurosphere generation was studied, analysing population doubling and the cell yield per animal. Secondary neurospheres were dissociated and plated on MCM Gel Cultrex 2D and after 6 d in vitro (DIVs) in mitogen withdrawal conditions, spontaneous differentiation was studied using specific neural markers (MAP2 and TuJ-1 for neurons, GFAP for astroglial cells and CNPase for oligodendrocytes). Gene expression pathways were analysed in secondary neurospheres, using the QIAGEN PCR array for neurogenesis, comparing the Tg2576 derived cell expression with the Wt cells. Proteins encoded by the altered genes were clustered using STRING web software.
RESULTS: As revealed by 6E10 positive staining, all Tg2576 derived cells retain the expression of the human transgenic Amyloid Precursor Protein. Tg2576 derived primary neurospheres show a decrease in population doubling. Morphological analysis of differentiated NSCs reveals a decrease in MAP2- and an increase in GFAP-positive cells in Tg2576 derived cells. Analysing the branching of TuJ-1 positive cells, a clear decrease in neurite number and length is observed in Tg2576 cells. The gene expression neurogenesis pathway revealed 11 altered genes in Tg2576 NSCs compared to Wt.
CONCLUSION: Tg2576 NSCs represent an appropriate AD in vitro model resembling some cellular alterations observed in vivo, both as stem and differentiated cells.
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Sivilia S, Lorenzini L, Giuliani A, Gusciglio M, Fernandez M, Baldassarro VA, Mangano C, Ferraro L, Pietrini V, Baroc MF, Viscomi AR, Ottonello S, Villetti G, Imbimbo BP, Calzà L, Giardino L. Multi-target action of the novel anti-Alzheimer compound CHF5074: in vivo study of long term treatment in Tg2576 mice. BMC Neurosci 2013. [PMID: 23560952 DOI: 10.1186/1471-2202-14.44] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Alzheimer disease is a multifactorial disorder characterized by the progressive deterioration of neuronal networks. The pathological hallmarks includes extracellular amyloid plaques and intraneuronal neurofibrillary tangles, but the primary cause is only partially understood. Thus, there is growing interest in developing agents that might target multiple mechanisms leading to neuronal degeneration. CHF5074 is a nonsteroidal anti-inflammatory derivative that has been shown to behave as a γ-secretase modulator in vitro and to inhibit plaque deposition and to reverse memory deficit in vivo in transgenic mouse models of Alzheimer's disease (AD). In the present study, the effects of a long-term (13-month) treatment with CHF5074 on indicators of brain functionality and neurodegeneration in transgenic AD mice (Tg2576) have been assessed and compared with those induced by a prototypical γ-secretase inhibitor (DAPT). RESULTS To this end, plaque-free, 6-month-old Tg2576 mice and wild-type littermates were fed with a diet containing CHF5074 (125 and 375 ppm/day), DAPT (375 ppm/day) or vehicle for 13 months. The measured indicators included object recognition memory, amyloid burden, brain oligomeric and plasma Aβ levels, intraneuronal Aβ, dendritic spine density/morphology, neuronal cyclin A positivity and activated microglia. Tg2576 mice fed with standard diet displayed an impairment of recognition memory. This deficit was completely reverted by the higher dose of CHF5074, while no effects were observed in DAPT-treated mice. Similarly, amyloid plaque burden, microglia activation and aberrant cell cycle events were significantly affected by CHF5074, but not DAPT, treatment. Both CHF5074 and DAPT reduced intraneuronal Aβ content, also increasing Aβ40 and Aβ42 plasma levels. CONCLUSIONS This comparative analysis revealed a profoundly diverse range of clinically relevant effects differentiating the multifunctional anti-inflammatory derivative CHF5074 from the γ-secretase inhibitor DAPT and highlighted unique mechanisms and potential targets that may be crucial for neuroprotection in mouse models of AD.
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Affiliation(s)
- Sandra Sivilia
- Department of Veterinary Medicine, University of Bologna, Bologna, Italy
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Sivilia S, Lorenzini L, Giuliani A, Gusciglio M, Fernandez M, Baldassarro VA, Mangano C, Ferraro L, Pietrini V, Baroc MF, Viscomi AR, Ottonello S, Villetti G, Imbimbo BP, Calzà L, Giardino L. Multi-target action of the novel anti-Alzheimer compound CHF5074: in vivo study of long term treatment in Tg2576 mice. BMC Neurosci 2013; 14:44. [PMID: 23560952 PMCID: PMC3626610 DOI: 10.1186/1471-2202-14-44] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 03/14/2013] [Indexed: 02/08/2023] Open
Abstract
Background Alzheimer disease is a multifactorial disorder characterized by the progressive deterioration of neuronal networks. The pathological hallmarks includes extracellular amyloid plaques and intraneuronal neurofibrillary tangles, but the primary cause is only partially understood. Thus, there is growing interest in developing agents that might target multiple mechanisms leading to neuronal degeneration. CHF5074 is a nonsteroidal anti-inflammatory derivative that has been shown to behave as a γ-secretase modulator in vitro and to inhibit plaque deposition and to reverse memory deficit in vivo in transgenic mouse models of Alzheimer’s disease (AD). In the present study, the effects of a long-term (13-month) treatment with CHF5074 on indicators of brain functionality and neurodegeneration in transgenic AD mice (Tg2576) have been assessed and compared with those induced by a prototypical γ-secretase inhibitor (DAPT). Results To this end, plaque-free, 6-month-old Tg2576 mice and wild-type littermates were fed with a diet containing CHF5074 (125 and 375 ppm/day), DAPT (375 ppm/day) or vehicle for 13 months. The measured indicators included object recognition memory, amyloid burden, brain oligomeric and plasma Aβ levels, intraneuronal Aβ, dendritic spine density/morphology, neuronal cyclin A positivity and activated microglia. Tg2576 mice fed with standard diet displayed an impairment of recognition memory. This deficit was completely reverted by the higher dose of CHF5074, while no effects were observed in DAPT-treated mice. Similarly, amyloid plaque burden, microglia activation and aberrant cell cycle events were significantly affected by CHF5074, but not DAPT, treatment. Both CHF5074 and DAPT reduced intraneuronal Aβ content, also increasing Aβ40 and Aβ42 plasma levels. Conclusions This comparative analysis revealed a profoundly diverse range of clinically relevant effects differentiating the multifunctional anti-inflammatory derivative CHF5074 from the γ-secretase inhibitor DAPT and highlighted unique mechanisms and potential targets that may be crucial for neuroprotection in mouse models of AD.
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Affiliation(s)
- Sandra Sivilia
- Department of Veterinary Medicine, University of Bologna, Bologna, Italy
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Drummond ES, Muhling J, Martins RN, Wijaya LK, Ehlert EM, Harvey AR. Pathology associated with AAV mediated expression of beta amyloid or C100 in adult mouse hippocampus and cerebellum. PLoS One 2013; 8:e59166. [PMID: 23516609 PMCID: PMC3596293 DOI: 10.1371/journal.pone.0059166] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2012] [Accepted: 02/13/2013] [Indexed: 11/18/2022] Open
Abstract
Accumulation of beta amyloid (Aβ) in the brain is a primary feature of Alzheimer’s disease (AD) but the exact molecular mechanisms by which Aβ exerts its toxic actions are not yet entirely clear. We documented pathological changes 3 and 6 months after localised injection of recombinant, bi-cistronic adeno-associated viral vectors (rAAV2) expressing human Aβ40-GFP, Aβ42-GFP, C100-GFP or C100V717F-GFP into the hippocampus and cerebellum of 8 week old male mice. Injection of all rAAV2 vectors resulted in wide-spread transduction within the hippocampus and cerebellum, as shown by expression of transgene mRNA and GFP protein. Despite the lack of accumulation of Aβ protein after injection with AAV vectors, injection of rAAV2-Aβ42-GFP and rAAV2- C100V717F-GFP into the hippocampus resulted in significantly increased microgliosis and altered permeability of the blood brain barrier, the latter revealed by high levels of immunoglobulin G (IgG) around the injection site and the presence of IgG positive cells. In comparison, injection of rAAV2-Aβ40-GFP and rAAV2-C100-GFP into the hippocampus resulted in substantially less neuropathology. Injection of rAAV2 vectors into the cerebellum resulted in similar types of pathological changes, but to a lesser degree. The use of viral vectors to express different types of Aβ and C100 is a powerful technique with which to examine the direct in vivo consequences of Aβ expression in different regions of the mature nervous system and will allow experimentation and analysis of pathological AD-like changes in a broader range of species other than mouse.
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Affiliation(s)
- Eleanor S Drummond
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Western Australia, Australia.
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Zhang B, Tang XC, Zhang HY. Alternations of central insulin-like growth factor-1 sensitivity in APP/PS1 transgenic mice and neuronal models. J Neurosci Res 2013; 91:717-25. [PMID: 23401344 DOI: 10.1002/jnr.23201] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 11/10/2012] [Accepted: 12/17/2012] [Indexed: 11/06/2022]
Abstract
Although many post-mortem studies have found evidence of central insulin resistance in Alzheimer's disease (AD) patients, results on changes of central insulin-like growth factor-1 (IGF-1) signaling in the pathological process of AD remain controversial. In the present study, we observed the activation states of IGF-1 downstream signaling in brain slices of transgenic mice carrying APPswe/PS1dE9 mutations (APP/PS1 mice) at both early and late stages (ex vivo) and further investigated the involvement of oligomeric β-amyloid (Aβ) and Aβ-enriched culture medium (CM) on IGF-1 sensitivity employing neuronal models (in vitro). In 6- and 18-month-old APP/PS1 mice, the phosphorylations of IGF-1 receptor (IGF-1R) and Akt in response to IGF-1 stimulation were significantly reduced in the hippocampal and cortical slices, whereas IGF-1R protein expression and mRNA levels of IGF-1 and IGF-1R in the hippocampal slices were significantly higher than that in wild-type mice. In agreement with these results, reduced IGF-1 sensitivity was verified in APP and PS1 double stably transfected CHO cells; moreover, IGF-1 stimulated phosphorylations of IGF-1R and Akt were also markedly weakened by oligomeric Aβ or Aβ-enriched CM posttreatment in CHO cells without APP/PS1-transfected (K1 cells) and primary hippocampal neurons. These observations indicate that the impaired central IGF-1 sensitivity at early and late stages of APP/PS1 transgenic mice might be attributable, at least partially, to the overproduced Aβ, especially the oligomeric Aβ. These findings may shed new light on the mechanisms underlying the defective IGF-1 signaling in AD pathogenesis and provide important clues for AD drug discovery.
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Affiliation(s)
- Bing Zhang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
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Hashimoto M, Bogdanovic N, Nakagawa H, Volkmann I, Aoki M, Winblad B, Sakai J, Tjernberg LO. Analysis of microdissected neurons by 18O mass spectrometry reveals altered protein expression in Alzheimer's disease. J Cell Mol Med 2012; 16:1686-700. [PMID: 21883897 PMCID: PMC3822682 DOI: 10.1111/j.1582-4934.2011.01441.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
It is evident that the symptoms of Alzheimer's disease (AD) are derived from severe neuronal damage, and especially pyramidal neurons in the hippocampus are affected pathologically. Here, we analysed the proteome of hippocampal neurons, isolated from post-mortem brains by laser capture microdissection. By using 18O labelling and mass spectrometry, the relative expression levels of 150 proteins in AD and controls were estimated. Many of the identified proteins are involved in transcription and nucleotide binding, glycolysis, heat-shock response, microtubule stabilization, axonal transport or inflammation. The proteins showing the most altered expression in AD were selected for immunohistochemical analysis. These analyses confirmed the altered expression levels, and showed in many AD cases a pathological pattern. For comparison, we also analysed hippocampal sections by Western blot. The expression levels found by this method showed poor correlation with the neuron-specific analysis. Hence, we conclude that cell-specific proteome analysis reveals differences in the proteome that cannot be detected by bulk analysis.
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Affiliation(s)
- Masakazu Hashimoto
- Karolinska Institutet and Dainippon Sumitomo Pharma Alzheimer Center, Department of Neurobiology, Care Sciences and Society, NVS, Karolinska Institutet, Huddinge, Sweden
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40
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Hampel H, Lista S, Khachaturian ZS. Development of biomarkers to chart all Alzheimer's disease stages: the royal road to cutting the therapeutic Gordian Knot. Alzheimers Dement 2012; 8:312-36. [PMID: 22748938 DOI: 10.1016/j.jalz.2012.05.2116] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The aim of this perspective article is to stimulate radical shifts in thinking and foster further discussion on the effective discovery, development, validation, and qualification process of biological markers derived from all available technical modalities that meet the complex conceptual and pathophysiological challenges across all stages of the complex, nonlinear, dynamic, and chronically progressive sporadic Alzheimer's disease (AD). This perspective evaluates the current state of the science regarding a broad spectrum of hypothesis-driven and exploratory technologies and "markers" as candidates for all required biomarker functions, in particular, surrogate indicators of adaptive to maladaptive and compensatory to decompensatory, reversible to irreversible brain "systems failure." We stress the future importance of the systems biology (SB) paradigm (next to the neural network paradigm) for substantial progress in AD research. SB represents an integrated and deeper investigation of interacting biomolecules within cells and organisms. This approach has only recently become feasible as high-throughput technologies and mass spectrometric analyses of proteins and lipids, together with rigorous bioinformatics, have evolved. Existing high-content data derived from clinically and experimentally derived neural tissues point to convergent pathophysiological pathways during the course of AD, transcending traditional descriptive studies to reach a more integrated and comprehensive understanding of AD pathophysiology, derived systems biomarkers, and "druggable" system nodes. The discussion is continued on the premise that the lack of integration of advanced biomarker technologies and transfertilization from more mature translational research fields (e.g., oncology, immunology, cardiovascular), which satisfy regulatory requirements for an accurate, sensitive, and well-validated surrogate marker of specific pathophysiological processes and/or clinical outcomes, is a major rate-limiting factor for the successful development and approval of effective treatments for AD prevention. We consider the conceptual, scientific, and technical challenges for the discovery-development-validation-qualification process of biomarker tools and analytical algorithms for detection of the earliest pathophysiological processes in asymptomatic individuals at elevated risk during preclinical stages of AD. The most critical need for rapid translation of putative markers into validated (performance) and standardized (harmonized standard operating procedures) biomarker tools that fulfill regulatory requirements (qualify for use in treatment trials: e.g., safety, target engagement, mechanism of action, enrichment, stratification, secondary and primary outcome, surrogate outcome) is the availability of a large-scale worldwide comprehensive longitudinal database that includes the following cohorts: (a) healthy aging, (b) people at elevated risks (genetic/epigenetic/lifestyle/comorbid conditions), and (c) asymptomatic-preclinical/prodromal-mild cognitive impairment/syndromal mild, moderate, or severe AD. Our proposal, as initial strategic steps for integrating markers into future development of diagnostic and therapy trial technologies, is to work toward: (a) creating the essential research and development infrastructure as an international shared resource, (b) building the organizational structure for managing such a multinational shared resource, and (c) establishing an integrated transsectoral multidisciplinary global network of collaborating investigators to help build and use the shared research resource.
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Affiliation(s)
- Harald Hampel
- Department of Psychiatry, University of Frankfurt, Frankfurt am Main, Germany.
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41
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Talbot K, Wang HY, Kazi H, Han LY, Bakshi KP, Stucky A, Fuino RL, Kawaguchi KR, Samoyedny AJ, Wilson RS, Arvanitakis Z, Schneider JA, Wolf BA, Bennett DA, Trojanowski JQ, Arnold SE. Demonstrated brain insulin resistance in Alzheimer's disease patients is associated with IGF-1 resistance, IRS-1 dysregulation, and cognitive decline. J Clin Invest 2012; 122:1316-38. [PMID: 22476197 DOI: 10.1172/jci59903] [Citation(s) in RCA: 1275] [Impact Index Per Article: 106.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
While a potential causal factor in Alzheimer's disease (AD), brain insulin resistance has not been demonstrated directly in that disorder. We provide such a demonstration here by showing that the hippocampal formation (HF) and, to a lesser degree, the cerebellar cortex in AD cases without diabetes exhibit markedly reduced responses to insulin signaling in the IR→IRS-1→PI3K signaling pathway with greatly reduced responses to IGF-1 in the IGF-1R→IRS-2→PI3K signaling pathway. Reduced insulin responses were maximal at the level of IRS-1 and were consistently associated with basal elevations in IRS-1 phosphorylated at serine 616 (IRS-1 pS⁶¹⁶) and IRS-1 pS⁶³⁶/⁶³⁹. In the HF, these candidate biomarkers of brain insulin resistance increased commonly and progressively from normal cases to mild cognitively impaired cases to AD cases regardless of diabetes or APOE ε4 status. Levels of IRS-1 pS⁶¹⁶ and IRS-1 pS⁶³⁶/⁶³⁹ and their activated kinases correlated positively with those of oligomeric Aβ plaques and were negatively associated with episodic and working memory, even after adjusting for Aβ plaques, neurofibrillary tangles, and APOE ε4. Brain insulin resistance thus appears to be an early and common feature of AD, a phenomenon accompanied by IGF-1 resistance and closely associated with IRS-1 dysfunction potentially triggered by Aβ oligomers and yet promoting cognitive decline independent of classic AD pathology.
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Affiliation(s)
- Konrad Talbot
- Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-3403, USA.
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Abstract
Alzheimer's disease (AD) is poised to become the most serious healthcare issue of our generation. The leading theory of AD pathophysiology is the Amyloid Cascade Hypothesis, and clinical trials are now proceeding based on this hypothesis. Here, we review the original evidence for the Amyloid Hypothesis, which was originally focused on the extracellular deposition of beta amyloid peptides (Aβ) in large fibrillar aggregates, as well as how this theory has been extended in recent years to focus on highly toxic small soluble amyloid oligomers. We will also examine emerging evidence that Aβ may actually begin to accumulate intracellularly in lysosomes, and the role for intracellular Aβ and lysosomal dysfunction may play in AD pathophysiology. Finally, we will review the clinical implications of these findings.
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Critical role of intraneuronal Aβ in Alzheimer's disease: technical challenges in studying intracellular Aβ. Life Sci 2012; 91:1153-8. [PMID: 22727791 DOI: 10.1016/j.lfs.2012.06.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2012] [Revised: 05/15/2012] [Accepted: 05/31/2012] [Indexed: 01/22/2023]
Abstract
AIMS Multiple lines of evidence have implicated β-amyloid (Aβ) in the pathogenesis of Alzheimer's disease (AD). However, the mechanism(s) whereby Aβ is involved in the disease process remains unclear. The dominant hypothesis in AD has been that Aβ initiates the disease via toxicity from secreted, extracellular Aβ aggregates. More recently, an alternative hypothesis has emerged focusing on a pool of Aβ that accumulates early on within AD vulnerable neurons of the brain. Although the topic of intraneuronal Aβ has been of major interest in the field, technical difficulties in detecting intraneuronal Aβ have also made this topic remarkably controversial. Here we review evidence pointing to the critical role of intraneuronal Aβ in AD and provide insights both into challenges faced in detecting intracellular Aβ and the prion-like properties of Aβ. MAIN METHODS Immunoprecipitation and Western blot are used for Aβ detection. KEY FINDINGS We highlight that a standard biochemical method can underestimate intraneuronal Aβ and that extracellular Aβ can up-regulate intracellular Aβ. We also show that detergent can remove intraneuronal Aβ. SIGNIFICANCE There is a growing awareness that intraneuronal Aβ is a key pathogenic pool of Aβ involved in causing synapse dysfunction. Difficulties in detecting intraneuronal Aβ are an insufficient reason for ignoring this critical pool of Aβ.
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44
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Cuello AC, Allard S, Ferretti MT. Evidence for the accumulation of Abeta immunoreactive material in the human brain and in transgenic animal models. Life Sci 2012; 91:1141-7. [PMID: 22705309 DOI: 10.1016/j.lfs.2012.05.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 05/11/2012] [Accepted: 05/24/2012] [Indexed: 12/19/2022]
Abstract
In this review we highlight the evidence for an intracellular origin of Abeta (Aβ) amyloid peptides as well as the observations for a pathological accumulation of these peptides in Alzheimer's disease and Down syndrome, as well as in transgenic animal models. We deliberate on the controversy as to whether the intracellular Aβ immunoreactive material is simply an accumulation of unprocessed full length amyloid precursor protein (APP) or a mix of processed APP fragments including Aβ. Finally, we discuss the possible pathological significance of these intracellular APP fragments and the expected future research directions regarding this thought-provoking problem.
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Affiliation(s)
- A Claudio Cuello
- Department of Pharmacology and Therapeutics, McGill University, 3655 Sir William Osler Promenade, Room 1210, Montreal, Quebec, Canada.
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45
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Ferreiro E, Baldeiras I, Ferreira IL, Costa RO, Rego AC, Pereira CF, Oliveira CR. Mitochondrial- and endoplasmic reticulum-associated oxidative stress in Alzheimer's disease: from pathogenesis to biomarkers. Int J Cell Biol 2012; 2012:735206. [PMID: 22701485 PMCID: PMC3373122 DOI: 10.1155/2012/735206] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Accepted: 04/06/2012] [Indexed: 12/23/2022] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia in the elderly, affecting several million of people worldwide. Pathological changes in the AD brain include the presence of amyloid plaques, neurofibrillary tangles, loss of neurons and synapses, and oxidative damage. These changes strongly associate with mitochondrial dysfunction and stress of the endoplasmic reticulum (ER). Mitochondrial dysfunction is intimately linked to the production of reactive oxygen species (ROS) and mitochondrial-driven apoptosis, which appear to be aggravated in the brain of AD patients. Concomitantly, mitochondria are closely associated with ER, and the deleterious crosstalk between both organelles has been shown to be involved in neuronal degeneration in AD. Stimuli that enhance expression of normal and/or folding-defective proteins activate an adaptive unfolded protein response (UPR) that, if unresolved, can cause apoptotic cell death. ER stress also induces the generation of ROS that, together with mitochondrial ROS and decreased activity of several antioxidant defenses, promotes chronic oxidative stress. In this paper we discuss the critical role of mitochondrial and ER dysfunction in oxidative injury in AD cellular and animal models, as well as in biological fluids from AD patients. Progress in developing peripheral and cerebrospinal fluid biomarkers related to oxidative stress will also be summarized.
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Affiliation(s)
- E. Ferreiro
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Largo Marquês de Pombal 3004-517, Coimbra, Portugal
| | - I. Baldeiras
- Faculty of Medicine, University of Coimbra, Rua Larga 3004-504, Coimbra, Portugal
- University Coimbra Hospital, 3000-075, Coimbra, Portugal
| | - I. L. Ferreira
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Largo Marquês de Pombal 3004-517, Coimbra, Portugal
| | - R. O. Costa
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Largo Marquês de Pombal 3004-517, Coimbra, Portugal
| | - A. C. Rego
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Largo Marquês de Pombal 3004-517, Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Rua Larga 3004-504, Coimbra, Portugal
| | - C. F. Pereira
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Largo Marquês de Pombal 3004-517, Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Rua Larga 3004-504, Coimbra, Portugal
| | - C. R. Oliveira
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Largo Marquês de Pombal 3004-517, Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Rua Larga 3004-504, Coimbra, Portugal
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Hoxha E, Boda E, Montarolo F, Parolisi R, Tempia F. Excitability and synaptic alterations in the cerebellum of APP/PS1 mice. PLoS One 2012; 7:e34726. [PMID: 22511962 PMCID: PMC3325253 DOI: 10.1371/journal.pone.0034726] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 03/08/2012] [Indexed: 12/16/2022] Open
Abstract
In Alzheimer's disease (AD), the severity of cognitive symptoms is better correlated with the levels of soluble amyloid-beta (Aβ) rather than with the deposition of fibrillar Aβ in amyloid plaques. In APP/PS1 mice, a murine model of AD, at 8 months of age the cerebellum is devoid of fibrillar Aβ, but dosage of soluble Aβ1–42, the form which is more prone to aggregation, showed higher levels in this structure than in the forebrain. Aim of this study was to investigate the alterations of intrinsic membrane properties and of synaptic inputs in Purkinje cells (PCs) of the cerebellum, where only soluble Aβ is present. PCs were recorded by whole-cell patch-clamp in cerebellar slices from wild-type and APP/PS1 mice. In APP/PS1 PCs, evoked action potential discharge showed enhanced frequency adaptation and larger afterhyperpolarizations, indicating a reduction of the intrinsic membrane excitability. In the miniature GABAergic postsynaptic currents, the largest events were absent in APP/PS1 mice and the interspike intervals distribution was shifted to the left, but the mean amplitude and frequency were normal. The ryanodine-sensitive multivescicular release was not altered and the postsynaptic responsiveness to a GABAA agonist was intact. Climbing fiber postsynaptic currents were normal but their short-term plasticity was reduced in a time window of 100–800 ms. Parallel fiber postsynaptic currents and their short-term plasticity were normal. These results indicate that, in the cerebellar cortex, chronically elevated levels of soluble Aβ1–42 are associated with alterations of the intrinsic excitability of PCs and with alterations of the release of GABA from interneurons and of glutamate from climbing fibers, while the release of glutamate from parallel fibers and all postsynaptic mechanisms are preserved. Thus, soluble Aβ1–42 causes, in PCs, multiple functional alterations, including an impairment of intrinsic membrane properties and synapse-specific deficits, with differential consequences even in different subtypes of glutamatergic synapses.
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Affiliation(s)
- Eriola Hoxha
- Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Turin, Turin, Italy
| | - Enrica Boda
- Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Turin, Turin, Italy
| | - Francesca Montarolo
- Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Turin, Turin, Italy
| | - Roberta Parolisi
- Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Turin, Turin, Italy
| | - Filippo Tempia
- Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Turin, Turin, Italy
- National Institute of Neuroscience-Italy (INN), University of Turin, Turin Italy
- * E-mail:
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Intraneuronal Aβ accumulation and neurodegeneration: lessons from transgenic models. Life Sci 2012; 91:1148-52. [PMID: 22401905 DOI: 10.1016/j.lfs.2012.02.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 01/25/2012] [Accepted: 02/03/2012] [Indexed: 12/14/2022]
Abstract
AIMS In the present review we summarize current knowledge on the concept of intraneuronal Aβ as a determinant for neuron loss and other pathological alterations in transgenic models for Alzheimer disease. MAIN METHODS We discuss the use of transgenic mouse and non-vertebrate transgenic models accumulating intracellular Aβ peptides and their impact on the ongoing discussion. KEY FINDINGS Intraneuronal Aβ accumulation in transgenic models is intimately linked to pathological alterations including neuron loss. One of the technical caveats for visualizing intraneuronal Aβ is the antibody used to unequivocally demonstrate its presence. Very often antibodies were used that recognize both Aβ and APP, leading to false positive results due to misinterpretation. SIGNIFICANCE Whereas a clear relationship between intraneuronal Aβ accumulation and neuron loss is evident in transgenic mouse models it remains an unresolved issue whether the concept of intraneuronal Aβ can be integrated into the human pathology as well.
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Hedskog L, Petersen CAH, Svensson AI, Welander H, Tjernberg LO, Karlström H, Ankarcrona M. γ-Secretase complexes containing caspase-cleaved presenilin-1 increase intracellular Aβ(42) /Aβ(40) ratio. J Cell Mol Med 2012; 15:2150-63. [PMID: 21054783 PMCID: PMC4394225 DOI: 10.1111/j.1582-4934.2010.01208.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Markers for caspase activation and apoptosis have been shown in brains of Alzheimer's disease (AD) patients and AD-mouse models. In neurons, caspase activation is associated with elevated amyloid β-peptide (Aβ) production. Caspases cleave numerous substrates including presenilin-1 (PS1). The cleavage takes place in the large cytosolic loop of PS1-C-terminal fragment (PS1CTF), generating a truncated PS1CTF lacking half of the loop domain (caspCTF). The loop has been shown to possess important regulatory functions with regard to Aβ(40) and Aβ(42) production. Previously, we have demonstrated that γ-secretase complexes are active during apoptosis regardless of caspase cleavage in the PS1CTF-loop. Here, a PS1/PS2-knockout mouse blastocyst-derived cell line was used to establish stable or transient cell lines expressing either caspCTF or full-length CTF (wtCTF). We show that caspCTF restores γ-secretase activity and forms active γ-secretase complexes together with Nicastrin, Pen-2, Aph-1 and PS1-N-terminal fragment. Further, caspCTF containing γ-secretase complexes have a sustained capacity to cleave amyloid precursor protein (APP) and Notch, generating APP and Notch intracellular domain, respectively. However, when compared to wtCTF cells, caspCTF cells exhibit increased intracellular production of Aβ(42) accompanied by increased intracellular Aβ(42) /Aβ(40) ratio without changing the Aβ secretion pattern. Similarly, induction of apoptosis in wtCTF cells generate a similar shift in intracellular Aβ pattern with increased Aβ(42) /Aβ(40) ratio. In summary, we show that caspase cleavage of PS1 generates a γ-secretase complex that increases the intracellular Aβ(42) /Aβ(40) ratio. This can have implications for AD pathogenesis and suggests caspase inhibitors as potential therapeutic agents.
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Affiliation(s)
- Louise Hedskog
- KI-Alzheimer's Disease Research Center, Karolinska Institutet, Department of Neurobiology, Care Sciences and Society, Stockholm, Sweden
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Amyloid neuropathology in the single Arctic APP transgenic model affects interconnected brain regions. Neurobiol Aging 2011; 33:831.e11-9. [PMID: 21880397 DOI: 10.1016/j.neurobiolaging.2011.07.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2011] [Revised: 07/08/2011] [Accepted: 07/19/2011] [Indexed: 11/21/2022]
Abstract
The Arctic APP mutation (E693G) within the amyloid β (Aβ) domain of amyloid precursor protein (APP) leads to dementia with clinical features similar to Alzheimer's disease (AD), which is believed to be mediated via increased formation of protofibrils. We have generated a transgenic mouse model, TgAPParc, with neuron-specific expression of human amyloid precursor protein with the Arctic mutation (hAPParc), showing mild amyloid pathology with a relatively late onset. Here we performed a detailed analysis of the spatiotemporal progression of neuropathology in homozygous TgAPParc, focusing on intracellular Aβ and diffuse Aβ aggregates rather than amyloid plaques. We show that the neuropathology in homozygous TgAPParc mice starts with intracellular Aβ aggregates, which is followed by diffuse extracellular Aβ deposits in subiculum that later expands to brain regions receiving neuronal projections from regions already affected. Together this suggests that the pathology in TgAPParc mice affects interconnected brain regions and may represent a valuable tool to study the spread and progression of neuropathology in Alzheimer's disease.
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50
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Mangialasche F, Solomon A, Winblad B, Mecocci P, Kivipelto M. Alzheimer's disease: clinical trials and drug development. Lancet Neurol 2010; 9:702-16. [PMID: 20610346 DOI: 10.1016/s1474-4422(10)70119-8] [Citation(s) in RCA: 815] [Impact Index Per Article: 58.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Alzheimer's disease is the most common cause of dementia in elderly people. Research into Alzheimer's disease therapy has been at least partly successful in terms of developing symptomatic treatments, but has also had several failures in terms of developing disease-modifying therapies. These successes and failures have led to debate about the potential deficiencies in our understanding of the pathogenesis of Alzheimer's disease and potential pitfalls in diagnosis, choice of therapeutic targets, development of drug candidates, and design of clinical trials. Many clinical and experimental studies are ongoing, but we need to acknowledge that a single cure for Alzheimer's disease is unlikely to be found and that the approach to drug development for this disorder needs to be reconsidered. Preclinical research is constantly providing us with new information on pieces of the complex Alzheimer's disease puzzle, and an analysis of this information might reveal patterns of pharmacological interactions instead of single potential drug targets. Several promising randomised controlled trials are ongoing, and the increased collaboration between pharmaceutical companies, basic researchers, and clinical researchers has the potential to bring us closer to developing an optimum pharmaceutical approach for the treatment of Alzheimer's disease.
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